High-temperature characterization of polymers with HPLC system having multiple mobile-phase reservoirs

ABSTRACT

Rapid characterization and screening of polymer samples to determine average molecular weight, molecular weight distribution and other properties is disclosed. Rapid flow characterization systems and methods, including liquid chromatography and flow-injection analysis systems and methods are preferably employed. High throughput, automated sampling systems and methods, high-temperature characterization systems and methods, and rapid, indirect calibration compositions and methods are also disclosed. The described methods, systems, and devices have primary applications in combinatorial polymer research and in industrial process control.

[0001] This application claims priority under 35 U.S.C. Sec. 119(e) toU.S. Provisional Application Ser. No. 60/080,652, filed Apr. 3, 1998 bySafir et al., which is hereby incorporated by reference for allpurposes.

[0002] This application is related to the following U.S. patentapplications filed on the date even herewith, each of which is herebyincorporated by reference for all purposes: Ser. No. ______, entitled“Automated Sampling Methods for Rapid Characterization of Polymers”,filed Apr. 2, 1999 by Petro et al. under Attorney Docket No. 99-10; Ser.No. ______, entitled “Rapid Characterization of Polymers”, filed Apr. 2,1999 by Safir et al. under Attorney Docket No. 99-9; Ser. No. ______,entitled “Flow-Injection Analysis and Variable-Flow Light ScatteringApparatus and Methods for Characterizing Polymers”, filed Apr. 2, 1999by Nielsen et al. under Attorney Docket No. 99-12; and Ser. No. ______,entitled “Indirect Calibration of Polymer Characterization Systems”,filed Apr. 2, 1999 by Petro et al. under Attorney Docket No. 99-13.

BACKGROUND OF INVENTION

[0003] The present invention generally relates to the field of polymercharacterization. In particular, the invention relates to liquidchromatography and related flow-injection analysis techniques forrapidly characterizing polymer solutions, emulsions and dispersions, andto devices for implementing such techniques. In preferred embodiments,the characterization of a polymer sample or of components thereof iseffected with optical detectors. The methods and devices disclosedherein are applicable, inter alia, to the rapid characterization oflibraries of polymers prepared by combinatorial materials sciencetechniques.

[0004] Currently, there is substantial research activity directed towardthe discovery and optimization of polymeric materials for a wide rangeof applications. Although the chemistry of many polymers andpolymerization reactions has been extensively studied, it is,nonetheless, rarely possible to predict a priori the physical orchemical properties a particular polymeric material will possess or theprecise composition and architecture that will result from anyparticular synthesis scheme. Thus, characterization techniques todetermine such properties are an essential part of the discoveryprocess.

[0005] Combinatorial chemistry refers generally to methods forsynthesizing a collection of chemically diverse materials and to methodsfor rapidly testing or screening this collection of materials fordesirable performance characteristics and properties. Combinatorialchemistry approaches have greatly improved the efficiency of discoveryof useful materials. For example, material scientists have developed andapplied combinatorial chemistry approaches to discover a variety ofnovel materials, including for example, high temperaturesuperconductors, magnetoresistors, phosphors and catalysts. See, forexample, U.S. Pat. No. 5,776,359 to Schultz et al. In comparison totraditional materials science research, combinatorial materials researchcan effectively evaluate much larger numbers of diverse compounds in amuch shorter period of time. Although such high-throughput synthesis andscreening methodologies are conceptually promising, substantialtechnical challenges exist for application thereof to specific researchand commercial goals.

[0006] Methods have been developed for the combinatorial (e.g.,rapid-serial or parallel) synthesis and screening of libraries of smallmolecules of pharmaceutical interest, and of biological polymers such aspolypeptides, proteins, oligonucleotides and deoxyribonucleic acid (DNA)polymers. However, there have been few reports of the application ofcombinatorial techniques to the field of polymer science for thediscovery of new polymeric materials or polymerization catalysts or newsynthesis or processing conditions. Brocchini et al. describe thepreparation of a polymer library for selecting biomedical implantmaterials. See S. Brocchini et al., A Combinatorial Approach for PolymerDesign, J. Am. Chem. Soc. 119, 4553-4554 (1997). However, Brocchini etal. reported that each synthesized candidate material was individuallyprecipitated, purified, and then characterized according to “routineanalysis” that included gel permeation chromatography to measuremolecular weight and polydispersities. As such, Brocchini et al. did notaddress the need for efficient and rapid characterization of polymers.

[0007] Liquid chromatography is well known in the art for characterizinga polymer sample. Liquid chromatographic techniques employ separation ofone or more components of a polymer sample from other components thereofby flow through a chromatographic column, followed by detection of theseparated components with a flow-through detector. Approaches for liquidchromatography can vary, however, with respect to the basis ofseparation and with respect to the basis of detection. Gel permeationchromatography (GPC), a well-known form of size exclusion chromatography(SEC), is a frequently-employed chromatographic technique for polymersize determination. In GPC, the polymer sample is separated intocomponents according to the hydrodynamic volume occupied by eachcomponent in solution. More specifically, a polymer sample is injectedinto a mobile phase of a liquid chromatography system and is passedthrough one or more chromatographic columns packed with porous beads.Molecules with relatively small hydrodynamic volumes diffuse into thepores of the beads and remain therein for longer periods, and thereforeexit the column after molecules with relatively larger hydrodynamicvolume. Hence, GPC can characterize one or more separated components ofthe polymer sample with respect to its effective hydrodynamic radius(R_(h)). Another chromatographic separation approach is illustrated byU.S. Pat. No. 5,334,310 to Frechet et al. and involves the use of aporous monolithic stationary-phase as a separation medium within thechromatographic column, combined with a mobile-phase compositiongradient. (See also, Petro et al, Molded Monolithic Rod of MacroporousPoly(styrene-co-divinylbenzene) as a Separation Medium for HPLCSynthetic Polymers: “On-Column” Precipitation-RedissolutionChromatography as an Alternative to Size Exclusion Chromatography ofStyrene Oligomers and Polymers, Anal. Chem., 68, 315-321 (1996); andPetro et al, Immobilization of Trypsin onto “Molded” Macroporous Poly(Glycidyl Methacrylate-co-Ethylene Dimethacrylate) Rods and Use of theConjugates as Bioreactors and for Affinity Chromatography, Biotechnologyand Bioengineering, Vol. 49, pp. 355-363 (1996)). Chromatographyinvolving the porous monolith is reportedly based on aprecipitation/redissolution phenomenon that separates the polymeraccording to size—with the precipitated polymer molecules selectivelyredissolving as the solvent composition is varied. The monolith providesthe surface area and permeation properties needed for proper separation.Other separation approaches are also known in the art, including forexample, normal-phase adsorption chromatography (with separation ofpolymer components being based on preferential adsorption betweeninteractive functionalities of repeating units and an adsorbingstationary-phase) and reverse-phase chromatography (with separation ofpolymer components being based on hydrophobic interactions between apolymer and a non-polar stationary-phase). After separation, a detectorcan measure a property of the polymer or of a polymer component—fromwhich one or more characterizing properties, such as molecular weightcan be determined as a function of time. Specifically, a number ofmolecular-weight related parameters can be determined, including forexample: the weight-average molecular weight (M_(w)), the number-averagemolecular weight (M_(n)), the molecular-weight distribution shape, andan index of the breadth of the molecular-weight distribution(M_(w)/M_(n)), known as the polydispersity index (PDI). Othercharacterizing properties, such as mass, particle size, composition orconversion can likewise be determined.

[0008] Flow-injection analysis techniques have been applied forcharacterizing small molecules, such as pigments. Typically, suchtechniques include the detection of a sample with a continuous-flowdetector—without chromatographic separation prior to detection. However,such approaches have not, heretofore, been applied in the art of polymercharacterization. Moreover, no effort has been put forth to optimizesuch approaches with respect to sample-throughput.

[0009] A variety of continuous-flow detectors have been used formeasurements in liquid chromatography systems. Common flow-throughdetectors include optical detectors such as a differential refractiveindex detector (RI), an ultraviolet-visible absorbance detector(UV-VIS), or an evaporative mass detector (EMD)—sometimes referred to asan evaporative light scattering detector (ELSD). Additional detectioninstruments, such as a static-light-scattering detector (SLS), adynamic-light-scattering detector (DLS), and/or a capillary-viscometricdetector (C/V) are likewise known for measurement of properties ofinterest. Light-scattering methods, both static and dynamic, areestablished in several areas of polymer analysis. Static lightscattering (SLS) can be used to measure M, and the radii of gyration(R_(g)) of a polymer in a dilute solution of known concentration.Dynamic light scattering (DLS) measures the fluctuations in thescattering signal as a function of time to determine the diffusionconstant of dissolved polymer chains or other scattering species indilute solution or of polymer particles comprising many chains in aheterogeneous system such as dilute emulsion or latex dispersion. Thehydrodynamic radius, R_(h), of the chains or particles can then becalculated based on well-established models.

[0010] Presently known liquid chromatography systems and flow-injectionanalysis systems are not suitable for efficiently screening largernumbers of polymer samples. Known chromatographic techniques cantypically take up to an hour for each sample to ensure a high degree ofseparation over the wide range of possible molecular weights (i.e.,hydrodynamic volumes) for a sample. The known chromatographic techniquescan be even longer if the sample is difficult to dissolve or if otherproblems arise. Additionally, polymer samples are typically prepared forcharacterization manually and individually, and some characterizationsystems require specially-designed sample containers and/or substantialdelay-times. For example, optical methods such as light-scatteringprotocols typically employ detector-specific cuvettes which are manuallyplaced in a proper location in the light-scattering instrument. Suchoptical protocols can also require a sample to thermally equilibrate forseveral minutes before measurement. Moreover, because of the nature ofmany commercial polymers and/or polymer samples—such as theirnon-polarity and insolubility in water and/or alcohols, theirheterogeneous nature, their lack of sequence specificity, among otheraspects, the methods, systems and devices developed in connection withthe biotechnological, pharmaceutical and clinical-diagnostic arts aregenerally not instructive for characterizing polymers. Hence, knownapproaches are not well suited to the rapid characterization ofpolymers.

[0011] Aspects of polymer characterization, such as sample preparationand polymer separation, have been individually and separatelyinvestigated. For example, Poché et al. report a system and approach forautomated high-temperature dissolution of polymer samples. See Poché etal., Use of Laboratory Robotics for Gel Permeation Chromatography SamplePreparation: Automation of High-Temperature Polymer Dissolution, J. AppLPolym. Sci., 64(8), 1613-1623 (1997). Stationary-phase media that reducechromatographic separation times of individual polymer samples have alsobeen reported. See, for example, Petro et al., Molded continuouspoly(styrene-co-divinylbenzene) rod as a separation medium for the veryfast separation of polymers; Comparison of the chromatographicproperties of the monolithic rod with columns packed with porous andno-porous beads in high-performance liquid chromatography, Journal ofChromatography A, 752, 59-66 (1996); and Petro et al., MonodisperseHydrolyzed Poly(glycidyl methacrylate-co-ethylene dimethacrylate) Beadsas a Stationary Phase for Normal-Phase HPLC, Anal. Chem., 69, 3131(1997). However, such approaches have not contemplated nor beenincorporated into protocols and systems suitable for large-scale, oreven moderate-scale, combinatorial chemistry research, and particularly,for combinatorial material science research directed to thecharacterization of polymers.

[0012] With the development of combinatorial techniques that allow forthe parallel synthesis of arrays comprising a vast number of diverseindustrially relevant polymeric materials, there is a need for methodsand devices and systems to rapidly characterize the properties of thepolymer samples that are synthesized

SUMMARY OF INVENTION

[0013] It is therefore an object of the present invention to providesystems and protocols for characterizing combinatorial libraries ofpolymer samples, and particularly, libraries of or derived frompolymerization product mixtures, to facilitate the discovery ofcommercially important polymeric materials, catalysts, polymerizationconditions and/or post-synthesis processing conditions. It is also anobject of the invention to provide polymer characterization systems andprotocols that can be employed in near-real-time industrial processcontrol.

[0014] Briefly, therefore, this invention provides methods and apparatusfor the rapid characterization or screening of polymers bychromatographic techniques and related flow-injection analysistechniques, and particularly, those employing optical detection methods.This invention provides a number of embodiments for such rapidcharacterization or screening of polymers and those embodiments can beemployed individually or combined together. More specifically, polymercharacterization approaches and devices are presented involving flowcharacterization and non-flow characterization, and with respect to bothof the same, involving rapid-serial, parallel, serial-parallel andhybrid parallel-serial approaches. Some preferred approaches andembodiments are directed to rapid-serial flow characterization ofpolymer samples.

[0015] Among the several significant aspects of the rapid-serial flowcharacterization techniques are protocols and systems related toautomated sampling, chromatographic separation (where applicable) and/ordetection—which individually and collectively improve thesample-throughput when applied to characterize a plurality of polymersamples. The automated polymer sampling can be effected at fastersampling rates, with equipment optimized for such purposes, and insequences that benefit overall throughput and/or minimize extraneoussteps. A number of chromatographic separation techniques can be employedto efficiently and effectively separate one or more of the variouscomponents of a heterogeneous polymer sample from one or more othercomponents thereof. Generally, such techniques relate to columngeometry, separation medium and mobile-phase medium. Certain approachesand systems disclosed herein involve improved aspects of detection. Inaddition, rapid, indirect calibration standards and methods impactoverall system speed. Moreover, several important aspects of theinvention have direct implications for high-temperature characterizationefforts (typically ranging from about 75° C. to about 225° C.).

[0016] Many of such aspects of the invention can be directly translatedfor use with parallel or serial-parallel protocols, in addition torapid-serial protocols. In a preferred embodiment, for example, aparallel or serial-parallel dynamic light-scattering system andprotocols can be used for polymer characterization with very high samplethroughput.

[0017] Hence the methods, systems and devices of the present inventionare particularly suited for screening of arrays of polymerizationproduct mixtures prepared in the course of combinatorial materialsdiscovery—thereby providing a means for effectively and efficientlycharacterizing large numbers of different polymeric materials. Whilesuch methods, systems and devices have commercial application incombinatorial materials science research programs, they can likewise beapplied in industrial process applications for near-real-time processmonitoring or process control.

[0018] Other features, objects and advantages of the present inventionwill be in part apparent to those skilled in art and in part pointed outhereinafter. All references cited in the instant specification areincorporated by reference for all purposes. Moreover, as the patent andnon-patent literature relating to the subject matter disclosed and/orclaimed herein is substantial, many relevant references are available toa skilled artisan that will provide further instruction with respect tosuch subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1A through FIG. 1F are schematic diagrams showing an overviewof polymer characterization process steps (FIG. 1A), a rapid-serialprotocol for effecting such steps (FIG. 1B) for a plurality of samples(s₁, S₂, S₃ . . . s_(n)) to obtain corresponding characterizing propertyinformation (p₁, p₂, p₃ . . . p_(n)), a parallel protocol for effectingsuch steps (FIG. 1C) and several parallel-serial hybrid protocols foreffecting such steps (FIG. 1D, FIG. 1E, FIG. 1F).

[0020]FIG. 2A and FIG. 2B are schematic diagrams illustrating liquidchromatography (FIG. 2A) and flow-injection analysis (FIG. 2B) flowcharacterization systems.

[0021]FIG. 3 is a schematic diagram illustrating an eight-port injectionvalve used for loading a polymer sample and for injection thereof into amobile phase of a flow characterization system.

[0022]FIG. 4 is a schematic diagram illustrating an automated samplingsystem.

[0023]FIG. 5A through FIG. 5C are views of several embodiments of atemperature-controlled auto-sampler injection probe. FIGS. 5A and 5B arecross-sectional side views of an auto-sampler probe having a resistivetemperature-control element (FIG. 5A) and a fluid heat-exchanger typetemperature-control element (FIG. 5B), respectively.

[0024]FIG. 5C is a perspective view of an auto-sampler probe having abody with a large thermal mass.

[0025]FIG. 6 is a schematic diagram illustrating a preferred embodimentof a liquid chromatography system having high-temperaturecharacterization capabilities.

[0026]FIG. 7A through FIG. 7D relate to preferred liquid chromatographyand flow-injection analysis systems and/or operational aspects thereof.FIGS. 7A and 7B are schematic diagrams illustrating preferredembodiments of flow characterization systems capable of use for liquidchromatography or flow-injection analysis and having a singlemicroprocessor control (FIG. 7A) or multi-microprocessor control (FIG.7B). FIG. 7C is a schematic diagram illustrating a preferred embodimentfor a flow-injection analysis system, referred to as a flow-injectionlight-scattering (FILS) system. FIG. 7D is a schematic diagramillustrating one approach for effecting control of the mobile-phaseflowrate in a variable-flow light-scattering system.

[0027]FIG. 8 is a graph of detector output (mv) versus time (minutes)illustrating the results from a gel permeation/adsorption HPLCseparation of a typical emulsion sample diluted by THF from Example 10.The upper trace is from a refractive index (RI) detector. The lower twotraces are from a static light-scattering detector (SLS) at 90° (middletrace) and at 15° (lower trace).

[0028]FIG. 9 is a graph of retentate amount (%) versus time (minutes)illustrating refractive index traces for latex particles of differentsizes (204 nm, 50 nm, 19 nm) from Example 11 following chromatographicseparation (main traces), and without chromatographic separation(superimposed traces in lower-left-hand corner).

[0029]FIG. 10 is a graph of detector response (mv) versus time (minutes)illustrating light-scattering traces (LS 90°13 upper set of traces) andrefractive index traces (RI—lower set of traces) for latex particles ofdifferent sizes (204 nm, 50 nm, 19 nm) under the same flow conditionsfrom Example 12.

[0030]FIGS. 11A and 11B are graphs showing the results of Example 15.FIG. 11A is a graph of detector response (au) versus time(minutes)—showing overlaid chromatographs from a set of polymerstandards. FIG. 11B is a calibration curve corresponding to the tracesof FIG. 11A.

[0031] FIGS. 12A through FIG. 12C are graphs showing the results ofExample 16. FIG. 12A is a graph of detector response (mv) versusretention time (minutes) and includes traces for each of a plurality ofserially-characterized samples—with the traces being electronicallyoverlaid on a single chromatograph. FIG. 12B is a graph of detectorresponse (mv) versus retention time (minutes) for a “single-shot”indirect calibration standard for the samples being characterized. FIG.12C is a graph of log molecular weight versus retention time (minutes)and is the calibration curve corresponding to FIG. 12B.

[0032]FIG. 13 is a graph of detector response (mv) versus retention time(minutes) as a chromatograph for a representative sample characterizedin Example 17.

[0033]FIGS. 14A and 14B are three-dimensional bar-graphs showing thedetermined weight-average molecular weight for each of the samples of alibrary of samples (identified by location in a 96-well microtiter-typesample-container having 8 rows and 12 columns) as characterized usingaccelerated SEC (FIG. 14A) and rapid SEC (FIG. 14B) approaches detailedin Example 18A.

[0034]FIGS. 15A through 15F are graphs showing data from Example 18B.FIGS. 15A through 15C show the determined weight-average molecularweight (FIG. 15A), the determined polydispersity index (FIG. 15B) andthe determined conversion (FIG. 15C) for each of the library samples(identified by location in a 96-well microtiter-type sample-containerhaving 8 rows and 12 columns) as characterized using an accelerated SECapproach. FIGS. 15D through 15F show the determined weight-averagemolecular weight (FIG. 15D), the determined polydispersity index (FIG.15E) and the determined conversion (FIG. 15F) for each of the librarysamples as characterized using an enhanced rapid SEC approach. For eachgraph, values for the determined properties are represented by relativesize of the circle indicated for that sample. The absence of a circlefor a particular sample indicates that the property was not determinedfor that particular sample.

[0035]FIGS. 16A and 16B are graphs of detector response (mv) versusretention time (minutes) for a polymer sample characterized in twodifferent liquid chromatography systems illustrated in Example 19. Thesystems were identical except with respect to the detector—one systememploying a RI detector (FIG. 16A) and the other system employing anELSD detector (FIG. 16B).

[0036]FIGS. 17A and 17B are three-dimensional bar graphs showing thedetermined conversion (FIG. 17A) and the determined weight-averagemolecular weight (FIG. 17B) for the polystyrene samples (columns 1-4),the polymethylmethacrylate samples (columns 4-6), the polybutylacrylatesamples (columns 7-9) and the polyvinylacetate samples (columns 10-12)characterized with SEC-adsorption chromatography approaches illustratedin Example 20.

[0037]FIGS. 18A and 18B show the results of high-temperaturecharacterization experiments of Example 21 A. FIG. 18A is a graph ofdetector response (mv) versus retention time (minutes) for seriallycharacterized polystyrene standards overlaid as a single trace. FIG. 18Bis a graph of log molecular weight versus retention time as acalibration curve for representative polyethylene standards.

[0038]FIGS. 19A and 19B show the results of high-temperaturecharacterization experiments of Example 21B. FIG. 19A is a graph ofdetector response (mv) versus retention time (minutes) for seriallycharacterized representative polystyrene standards and polyethylenestandards overlaid as a single trace. FIG. 19B is a graph of logmolecular weight versus retention time as a calibration curve forrepresentative polyethylene standards.

[0039]FIG. 20 is a graph of detector response (mv) versus retention time(minutes) with superimposed traces for a polyethylene (PE) polymersample characterized by liquid chromatography approach illustrated inExample 22. Elution of the PE sample was effectively controlled bycontrolling the temperature of the mobile phase—in a first experiment ascontinuously “hot trichlorobenzene (TCB)” and in a second experiment as“cold TCB” for about 2 minutes and then “hot TCB” for the remainder ofthe run.

[0040]FIGS. 21A and 21B are graphs of detector response (mv) versusretention time (minutes) and show the resulting chromatographs for thecharacterization of 96 polymer samples using the SLS detector (FIG. 21A)and the ELSD (FIG. 21B) in the very rapid flow-injectionlight-scattering approach illustrated in Example 23.

[0041]FIGS. 22A and 22B are graphs of detector response (mv) versusretention time (minutes) and are chromatographs for single-shotcalibration using eight pooled, commercially-available polyisobutylene(PMB) standards (FIG. 22A), and for eight pooled, particularly-selectedpolystyrene standards having hydrodynamic volumes that are substantiallythe same as the hydrodynamic volumes for the PIB standards (FIG. 22B),as determined in Example 25.

[0042]FIGS. 23A and 23B are graphs of log molecular weight versusretention time (minutes) developed in connection with Example 25. FIG.23A is an absolute (direct) polyisobutylene (PIB) calibration curveprepared from a set of nine commercially-available PIB standards thatwere individually and serially determined in nine separatecharacterization runs. FIG. 23B is an indirect PIB calibration curveprepared from a set of nine polystyrene (PS) standards preselected basedon hydrodynamic volume to correspond with certain PIB standards, andpooled to form a set of polystyrene standards (the small molecularweight standard being omitted), that were, effectively, a compositionsuitable for single-shot indirect calibration for polyisobutylene.

[0043]FIG. 24 is a schematic diagram illustrating a parallel, non-flow,non-immersion dynamic light-scattering (DLS) polymer characterizationsystem.

[0044] The invention is described in further detail below with referenceto the figures, in which like items are numbered the same in the severalfigures.

DETAILED DESCRIPTION OF THE INVENTION

[0045] In the present invention, methods and apparatus having featuresthat enable an effective combinatorial polymer research program areprovided. Such a research program may be directed, for example, toidentifying or optimizing commercially valuable polymers, catalysts orother materials, or to other research goals, such as processcharacterization and optimization. Other applications, includingindustrial process monitoring or control are also enabled by the presentinvention.

[0046] More specifically, polymer characterization approaches anddevices are presented involving flow characterization and non-flowcharacterization, and with respect to both of the same, involvingrapid-serial, parallel, serial-parallel and hybrid parallel-serialapproaches. Some preferred approaches and embodiments are directed torapid-serial flow characterization of polymer samples. Among the severalsignificant aspects of the rapid-serial flow characterization techniquesare protocols and systems related to automated sampling, chromatographicseparation (where applicable) and/or detection—which individually andcollectively improve the sample-throughput when applied to characterizea plurality of polymer samples.

[0047] With respect to automated polymer sampling, for example, aplurality of polymer samples can be loaded into a flow characterizationsystem using an auto-sampler having a very high sampling rate—less than10 seconds per sample, or in some embodiments, less than 5 seconds persample. Additionally, automated sample preparation can be effected in adirect rapid-serial manner (i.e., serial samplewithdrawal-preparation-loading). The plurality of samples can be loaded,moreover, into an injection valve having two sample-loops—therebyproviding a load-load capability wherein a second sample can be loadedwhile the first sample is being injected into the characterizationsystem.

[0048] With respect to chromatographic separation, a number oftechniques can be employed to efficiently and effectively separate oneor more of the various components of a heterogeneous polymer sample fromone or more other components thereof. For example, the column geometry,preferably in combination with the separation medium, can be optimizedto obtain the desired throughput. Preferred column geometries includerelatively short, high-aspect ratio columns (as compared to conventionalcolumns). Preferred separation media include a stationary phase selectedfor targeted separation ranges—for example, to quickly pass a highmolecular-weight fraction of a sample (e.g., > about 1000 D) whileretaining a low molecular-weight fraction of the sample. Otherseparation medium optimization approaches, such as combiningsize-exclusion chromatography (SEC) with an adsorption chromatography,are also preferred in some applications. The mobile phase of a liquidchromatography system can also be controlled to improvesample-throughput. For example, mobile-phase compositional gradients,mobile-phase temperature gradients or mobile-phase flowrate gradientscan be employed individually or collectively, and the time-rate ofchange of such gradients can affect separation performance. For someapplications, solvent selection can itself be optimized to improve theefficiency of loading and/or eluting the sample or components thereofonto/from the stationary phase.

[0049] For flow characterization systems generally (including bothliquid chromatography systems and flow-injection analysis systems), theflow-rate of the mobile phase can be increased substantially (e.g., by afactor of ten or more) relative to conventional flow characterizationsystems. The mobile phase flow rates can also be temporally varied as asample moves through a flow characterization system—for example, withrelatively high flowrates to advance the sample to a detector, andrelatively slow flowrates to detect a property of the sample or of acomponent thereof.

[0050] With respect to detection, a low-molecular weight insensitivemass detector, such as an evaporative light-scattering detector (ELSD)can be advantageously employed in liquid chromatography approaches incooperation with overlaid sample injection approaches. Specifically,trailing-edge components from a preceding sample and leading-edgecomponents from a succeeding sample can reside in a detection cavitysimultaneously, without compromising relevant data collection. Inaddition, rapid, indirect calibration standards and methods impactoverall system speed.

[0051] Several important aspects of the invention have directimplications for high-temperature characterization efforts (typicallyranging from about 75° C. to about 225° C.). With regard to polymersampling, for example, a directly heated auto-sampler probe is employed.Chromatographic columns of relatively small mass (as compared toconventional columns) allow for rapid thermal equilibrilization of thesystem. With respect to chromatographic separation, mobile-phasetemperature and composition gradients can be employed. Finally,detectors that are less-sensitive to variations in temperature, ascompared with typical high-temperature characterization detectors, offera greater degree of freedom for system configuration at reduced costs.

[0052] Many of such aspects of the invention can be directly translatedfor use with parallel or serial-parallel protocols, in addition torapid-serial protocols. In a preferred embodiment, for example, aparallel or serial-parallel dynamic light-scattering system andprotocols can be used for polymer characterization with very high samplethroughput.

[0053] These and other aspects of the invention are to be consideredexemplary and non-limiting, and are discussed in greater detail below.The several aspects of the polymer characterization methods and systemsdisclosed and claimed herein can be advantageously employed separately,or in combination to efficiently characterize polymeric materials. Inpreferred embodiments, these features are employed in combination toform a polymer characterization system that can operate as ahigh-throughput screen in a materials science research program directedto identifying and optimizing new polymers, new catalysts, newpolymerization reaction conditions and/or new post-synthesis processingconditions. Certain characterizing information—particularly molecularweight, molecular weight distribution, composition and conversioninformation—are broadly useful for characterizing polymers andpolymerization reactions. As such, the particular polymers and/ormechanisms disclosed herein should be considered exemplary of theinvention and non-limiting as to the scope of the invention.

[0054] Combinatorial Approaches for Polymer Science Research

[0055] In a combinatorial approach for identifying or optimizingpolymeric materials or polymerization reaction conditions, a largecompositional space (e.g., of monomers, comonomers, catalysts, catalystprecursors, solvents, initiators, additives, or of relative ratios oftwo or more of the aforementioned) and/or a large reaction conditionspace (e.g., of temperature, pressure and reaction time) may be rapidlyexplored by preparing polymer libraries and then rapidly screening suchlibraries. The polymer libraries can comprise, for example,polymerization product mixtures resulting from polymerization reactionsthat are varied with respect to such factors.

[0056] Combinatorial approaches for screening a polymer library caninclude an initial, primary screening, in which polymerization productmixtures are rapidly evaluated to provide valuable preliminary data and,optimally, to identify several “hits”—particular candidate materialshaving characteristics that meet or exceed certain predetermined metrics(e.g., performance characteristics, desirable properties, unexpectedand/or unusual properties, etc.). Such metrics may be defined, forexample, by the characteristics of a known or standard polymer orpolymerization scheme. Because local performance maxima may exist incompositional spaces between those evaluated in the primary screening ofthe first libraries or alternatively, in process-condition spacesdifferent from those considered in the first screening, it may beadvantageous to screen more focused polymer libraries (e.g., librariesfocused on a smaller range of compositional gradients, or librariescomprising compounds having incrementally smaller structural variationsrelative to those of the identified hits) and additionally oralternatively, subject the initial hits to variations in processconditions. Hence, a primary screen can be used reiteratively to explorelocalized and/or optimized compositional space in greater detail. Thepreparation and evaluation of more focused polymer libraries cancontinue as long as the high-throughput primary screen can meaningfullydistinguish between neighboring library compositions or compounds.

[0057] Once one or more hits have been satisfactorily identified basedon the primary screening, polymer and polymerization product librariesfocused around the primary-screen hits can be evaluated with a secondaryscreen—a screen designed to provide (and typically verified, based onknown materials, to provide) chemical process conditions that relatewith a greater degree of confidence to commercially-important processesand conditions than those applied in the primary screen. In manysituations, such improved “real-world-modeling” considerations areincorporated into the secondary screen at the expense of methodologyspeed (e.g., as measured by sample throughput) compared to acorresponding primary screen. Particular polymer materials, catalysts,reactants, polymerization conditions or post-synthesis processingconditions having characteristics that surpass the predetermined metricsfor the secondary screen may then be considered to be “leads.” Ifdesired, additional polymer or polymerization product libraries focusedabout such lead materials can be screened with additional secondaryscreens or with tertiary screens. Identified lead polymers, monomers,catalysts, catalyst precursors, initiators, additives or reactionconditions may be subsequently developed for commercial applicationsthrough traditional bench-scale and/or pilot scale experiments.

[0058] While the concept of primary screens and secondary screens asoutlined above provides a valuable combinatorial research model forinvestigating polymers and polymerization reactions, a secondary screenmay not be necessary for certain chemical processes where primaryscreens provide an adequate level of confidence as to scalability and/orwhere market conditions warrant a direct development approach.Similarly, where optimization of materials having known properties ofinterest is desired, it may be appropriate to start with a secondaryscreen. In general, the systems, devices and methods of the presentinvention may be applied as either a primary or a secondary screen,depending on the specific research program and goals thereof. See,generally, U.S. patent application Ser. No. 09/227,558 entitled“Apparatus and Method of Research for Creating and Testing NovelCatalysts, Reactions and Polymers”, filed Jan. 8, 1999 by Turner et al.,for further discussion of a combinatorial approach to polymer scienceresearch.

[0059] Polymer Characterization—General Approaches

[0060] According to the present invention, methods, systems and devicesare disclosed that improve the efficiency and/or effectiveness of thesteps necessary to characterize a polymer sample or a plurality ofpolymer samples (e.g., libraries of polymerization product mixtures). Inpreferred embodiments, a property of a plurality of polymer samples orof components thereof can be detected in a polymer characterizationsystem with an average sample-throughput sufficient for an effectivecombinatorial polymer science research program.

[0061] With reference to FIG. 1A, characterizing a polymer sample caninclude (A) preparing the sample (e.g., dilution), (B) injecting thesample into a mobile phase of a flow characterization system (e.g.,liquid chromatography system, flow-injection analysis system), (C)separating the sample chromatographically, (D) detecting a property ofthe polymer sample or of a component thereof, and/or (E) correlating thedetected property to a characterizing property of interest. As depictedin FIG. 1A, various characterization protocols may be employed involvingsome or all of the aforementioned steps. For example, a property of apolymer sample may be detected in a non-flow, static system either withpreparation (steps A and D) or without preparation (step D).Alternatively, a property of a polymer sample may be detected in a flowcharacterization system—either with or without sample preparation andeither with or without chromatographic separation. In characterizationprotocols involving flow characterization systems withoutchromatographic separation (referred to herein as flow-injectionanalysis systems) a property of a polymer sample may be detected in aflow-injection analysis system either with preparation (steps A, B andD) or without preparation (steps B and D). If chromatographic separationof a polymer sample is desired, a property of the sample may be detectedin a liquid chromatography system either with preparation (steps A, B, Cand D) or without preparation (steps B, C and D). While thephysically-detected property (e.g., refracted light, absorbed light,scattered light) from two samples being screened could be compareddirectly, in most cases the detected property is preferably correlatedto a characterizing property of interest (e.g., molecular weight) (stepE).

[0062] A plurality of polymer samples may be characterized as describedabove in connection with FIG. 1A. As a general approach for improvingthe sample throughput for a plurality of polymers, each of the steps,(A) through (E) of FIG. 1A applicable to a given characterizationprotocol can be optimized with respect to time and quality ofinformation, both individually and in combination with each other.Additionally or alternatively, each or some of such steps can beeffected in a rapid-serial, parallel, serial-parallel or hybridparallel-serial manner.

[0063] The throughput of a plurality of samples through a single step ina characterization process is improved by optimizing the speed of thatstep, while maintaining—to the extent necessary—the information-qualityaspects of that step. In many cases, such as with chromatographicseparation, speed can be gained at the expense of resolution of theseparated components. Although conventional research norms, developed inthe context in which research was rate-limited primarily by thesynthesis of polymer samples, may find such an approach less than whollysatisfactory, the degree of rigor can be entirely satisfactory for aprimary or a secondary screen of a combinatorial library of polymersamples. For combinatorial polymer research (and as well, for manyon-line process control systems), the quality of information should besufficiently rigorous to provide for scientifically acceptabledistinctions between the compounds or process conditions beinginvestigated, and for a secondary screen, to provide for scientificallyacceptable correlation (e.g., values or, for some cases, trends) withmore rigorous, albeit more laborious and time-consuming traditionalcharacterization approaches.

[0064] The throughput of a plurality of samples through a series ofsteps, where such steps are repeated for the plurality of samples, canalso be optimized. In one approach, one or more steps of the cycle canbe compressed relative to traditional approaches or can have leading orlagging aspects truncated to allow other steps of the same cycle tooccur sooner compared to the cycle with traditional approaches. Inanother approach, the earlier steps of a second cycle can be performedconcurrently with the later steps of a first cycle. For example, withreference to FIG. 1A in a rapid-serial approach for characterizing asample, sample preparation for a second sample in a series can beeffected while the first sample in the series is being separated and/ordetected. As another example, a second sample in a series can beinjected while the first sample in the series is being separated and/ordetected. These approaches, as well as others, are discussed in greaterdetail below.

[0065] A characterization protocol for a plurality of samples caninvolve a single-step process (e.g., direct, non-flow detection of aproperty of a polymer sample or of a component thereof, depicted as stepD of FIG. 1A). In a rapid-serial detection approach for a single-stepprocess, the plurality of polymer samples and a single detector areserially positioned in relation to each other for serial detection ofthe samples. In a parallel detection approach, two or more detectors areemployed to detect a property of two or more samples simultaneously. Ina direct, non-flow detection protocol, for example, two or more samplesand two or more detectors can be positioned in relation to each other todetect a property of the two or more polymer samples simultaneously. Ina serial-parallel detection approach, a property of a larger number ofpolymer samples (e.g., four or more) is detected as follows. First, aproperty of a subset of the four or more polymer samples (e.g., 2samples) is detected in parallel for the subset of samples, and thenserially thereafter, a property of another subset of four or moresamples is detected in parallel.

[0066] For characterization protocols involving more than one step(e.g., steps A, D and E; steps B, D and E; steps A, B, D and E; steps B,C, D and E; or steps A, B, C, D and E of FIG. 1A), optimizationapproaches to effect high-throughput polymer characterization can vary.As one example, represented schematically in FIG. 1B, a plurality ofpolymer samples can be characterized with a single polymercharacterization system (I) in a rapid-serial approach in which each ofthe plurality of polymer samples (s₁, s₂, s₃ . . . s_(n)) are processedserially through the characterization system (I) with each of the steps(A, B, C, D, E) effected in series on each of the of samples to producea serial stream of corresponding characterizing property information(p₁, p₂, p₃ . . . p_(n)). This approach benefits from minimal capitalinvestment, and may provide sufficient throughput—particularly when thesteps (A) through (E) have been optimized with respect to speed andquality of information. As another example, represented schematically inFIG. 1C, a plurality of polymer samples can be characterized with two ormore polymer characterization systems (I, II, III . . . N) in a pureparallel (or for larger libraries, serial-parallel) approach in whichthe plurality of polymer samples (s₁, s₂, s₃ . . . s_(n)) or a subsetthereof are processed through the two or more polymer characterizationsystems (I, II, III . . . N) in parallel, with each individual systemeffecting each step on one of the samples to produce the characterizingproperty information (p₁, p₂, p₃ . . . p_(n)) in parallel. This approachis advantageous with respect to overall throughput, but may beconstrained by the required capital investment.

[0067] In a hybrid approach, certain of the steps of thecharacterization process can be effected in parallel, while certainother steps can be effected in series. Preferably, for example, it maybe desirable to effect the longer, throughput-limiting steps in parallelfor the plurality of samples, while effecting the faster, less limitingsteps in series. Such a parallel-series hybrid approach can beexemplified, with reference to FIG. 1D, by parallel sample preparation(step A) of a plurality of polymer samples (s₁, s₂, s₃ . . . s_(n)),followed by serial injection, chromatographic separation, detection andcorrelation (steps B, C, D and E) with a single characterization system(I) to produce a serial stream of corresponding characterizing propertyinformation (p₁, p₂, p₃ . . . p_(n)). In another exemplaryparallel-series hybrid approach, represented schematically in FIG. 1E, aplurality of polymer samples (s₁, s₂, s₃ . . . s_(n)) are prepared andinjected in series into the mobile phase of four or more liquidchromatography characterizing systems (I, II, III . . . N), and thenseparated, detected and correlated in a slightly offset (staggered)parallel manner to produce the characterizing property information (p₁,p₂, p₃ . . . p_(n)) in the same staggered-parallel manner. If each ofthe separation and detection systems has the same processing rates, thenthe extent of the parallel offset (or staggering) will be primarilydetermined by the speed of the serial preparation and injection. In avariation of the preceding example, with reference to FIG. 1F, where thedetection and correlation steps are sufficient fast, a plurality ofpolymer samples (s₁, s₂, s₃ . . . s_(n)) could be characterized byserial sample preparation and injection, staggered-parallelchromatographic separation, and then serial detection and correlation,to produce the characterizing property information (p₁, p₂, p₃ . . .p_(n)) in series. In this case, the rate of injection into the variousseparation columns is preferably synchronized with the rate ofdetection.

[0068] Optimization of individual characterization steps (e.g., steps(A) through (E) of FIG. 1A) with respect to speed and quality ofinformation can improve sample throughput regardless of whether theoverall characterization scheme involves a rapid-serial or parallelaspect (i.e., true parallel, serial-parallel or hybrid parallel-seriesapproaches). As such, the optimization techniques disclosed hereinafter,while discussed primarily in the context of a rapid-serial approach, arenot limited to such an approach, and will have application to schemesinvolving parallel characterization protocols.

[0069] Polymer Samples

[0070] The polymer sample can be a homogeneous polymer sample or aheterogeneous polymer sample, and in either case, comprises one or morepolymer components. As used herein, the term “polymer component” refersto a sample component that includes one or more polymer molecules. Thepolymer molecules in a particular polymer component have the same repeatunit, and can be structurally identical to each other or structurallydifferent from each other. For example, a polymer component may comprisea number of different molecules, with each molecule having the samerepeat unit, but with a number of molecules having different molecularweights from each other (e.g., due to a different degree ofpolymerization). As another example, a heterogeneous mixture ofcopolymer molecules may, in some cases, be included within a singlepolymer component (e.g., a copolymer with a regularly-occurring repeatunit), or may, in other cases, define two or more different polymercomponents (e.g., a copolymer with irregularly-occurring orrandomly-occurring repeat units). Hence, different polymer componentsinclude polymer molecules having different repeat units. It is possiblethat a particular polymer sample (e.g., a member of a library) will notcontain a particular polymer molecule or polymer component of interest.

[0071] The polymer molecule of the polymer component is preferably anon-biological polymer. A non-biological polymer is, for purposesherein, a polymer other than an amino-acid polymer (e.g., protein) or anucleic acid polymer (e.g., deoxyribonucleic acid (DNA)). Thenon-biological polymer molecule of the polymer component is, however,not generally critical; that is, the systems and methods disclosedherein will have broad application with respect to the type (e.g.,architecture, composition, synthesis method or mechanism) and/or nature(e.g., physical state, form, attributes) of the non-biological polymer.Hence, the polymer molecule can be, with respect to homopolymer orcopolymer architecture, a linear polymer, a branched polymer (e.g.,short-chain branched, long-chained branched, hyper-branched), across-linked polymer, a cyclic polymer or a dendritic polymer. Acopolymer molecule can be a random copolymer molecule, a block copolymermolecule (e.g., di-block, tri-block, multi-block, taper-block), a graftcopolymer molecule or a comb copolymer molecule. The particularcomposition of the non-biological polymer molecule is not critical, andcan include repeat units or random occurrences of one or more of thefollowing, without limitation: polyethylene, polypropylene, polystyrene,polyolefin, polyimide, polyisobutylene, polyacrylonitrile, poly(vinylchloride), poly(methyl methacrylate), poly(vinyl acetate),poly(vinylidene chloride), polytetrafluoroethylene, polyisoprene,polyacrylamide, polyacrylic acid, polyacrylate, poly(ethylene oxide),poly(ethyleneimine), polyamide, polyester, polyurethane, polysiloxane,polyether, polyphosphazine, polymethacrylate, and polyacetals.Polysaccharides are also preferably included within the scope ofnon-biological polymers. While some polysaccharides are of biologicalsignificance, many polysaccharides, and particularly semi-syntheticpolysaccharides have substantial industrial utility with little, if anybiological significance. Exemplary naturally-occurring polysaccharidesinclude cellulose, dextran, gums (e.g., guar gum, locust bean gum,tamarind xyloglucan, pullulan), and other naturally-occurring biomass.Exemplary semi-synthetic polysaccharides having industrial applicationsinclude cellulose diacetate, cellulose triacetate, acylated cellulose,carboxymethyl cellulose and hydroxypropyl cellulose. In any case, suchnaturally-occurring and semi-synthetic polysaccharides can be modifiedby reactions such as hydrolysis, esterification, alkylation, or by otherreactions.

[0072] In typical applications, a polymer sample is a heterogeneoussample comprising one or more polymer components, one or more monomercomponents and/or a continuous fluid phase. In copolymer applications,the polymer sample can comprise one or more copolymers, a firstcomonomer, a second comonomer, additional comonomers, and/or acontinuous fluid phase. The polymer samples can, in any case, alsoinclude other components, such as catalysts, catalyst precursors (e.g.,ligands, metal-precursors), solvents, initiators, additives, products ofundesired side-reactions (e.g., polymer gel, or undesired homopolymer orcopolymers) and/or impurities. Typical additives include, for example,surfactants, control agents, plasticizers, cosolvents and/oraccelerators, among others. The various components of the heterogeneouspolymer sample can be uniformly or non-uniformly dispersed in thecontinuous fluid phase.

[0073] The polymer sample is preferably a liquid polymer sample, such asa polymer solution, a polymer emulsion, a polymer dispersion or apolymer that is liquid in the pure state (i.e., a neat polymer). Apolymer solution comprises one or more polymer components dissolved in asolvent. The polymer solution can be of a form that includeswell-dissolved chains and/or dissolved aggregated micelles. The solventcan vary, depending on the application, for example with respect topolarity, volatility, stability, and/or inertness or reactivity. Typicalsolvents include, for example, tetrahydrofuran (THF), toluene, hexane,ethers, trichlorobenzene, dichlorobenzene, dimethylformamide, water,aqueous buffers, alcohols, etc. According to traditional chemistryconventions, a polymer emulsion can be considered to comprise one ormore liquid-phase polymer components emulsified (uniformly ornon-uniformly) in a liquid continuous phase, and a polymer dispersioncan be considered to comprise solid particles of one or more polymercomponents dispersed (uniformly or non-uniformly) in a liquid continuousphase. The polymer emulsion and the polymer dispersion can also beconsidered, however, to have the more typically employed meaningsspecific to the art of polymer science—of being aemulsion-polymerization product and dispersion-polymerization product,respectively. In such cases, for example, the emulsion polymer samplecan more generally include one or more polymer components that areinsoluble, but uniformly dispersed, in a continuous phase, with typicalemulsions including polymer component particles ranging in diameter fromabout 2 nm to about 500 nm, more typically from about 20 nm to about 400nm, and even more typically from about 40 nm to about 200 nm. Thedispersion polymer sample can, in such cases, generally include polymercomponent particles that are dispersed (uniformly or nonuniformly) in acontinuous phase, with typical particles having a diameter ranging fromabout 0.2 μm to about 1000 μm, more typically from about 0.4 μm to about500 μm, and even more typically from about 0.5 μm to about 200 μm.Exemplary polymers that can be in the form of neat polymer samplesinclude dendrimers, and siloxane, among others. The liquid polymersample can also be employed in the form of a slurry, a latex, a microgela physical gel, or in any other form sufficiently tractable for analysisas described and claimed herein. Liquid samples are useful in theautomated sample-handling tools that prepare and automatically sampleeach member of a polymer library. Liquid samples also allow the sampleto flow in the chromatographic system or characterization system. Insome cases, polymer synthesis reactions (i.e., polymerizations) directlyproduce liquid samples. These may be bulk liquid polymers, polymersolutions, or heterogeneous liquid samples such as polymer emulsions,latices, or dispersions. In other cases, the polymer may be synthesized,stored or otherwise available for characterization in a non-liquidphysical state, such as a solid state (e.g., crystalline,semicrystalline or amorphous), a glassy state or rubbery state. Hence,the polymer sample may need to be dissolved, dispersed or emulsified toform a liquid sample by addition of a continuous liquid-phase such as asolvent. The polymer sample can, regardless of its particular form, havevarious attributes, including variations with respect to polarity,solubility and/or miscibility.

[0074] In preferred applications, the polymer sample is a polymerizationproduct mixture. As used herein, the term “polymerization productmixture” refers to a mixture of sample components obtained as a productfrom a polymerization reaction. An exemplary polymerization productmixture can be a sample from a combinatorial library prepared bypolymerization reactions, or can be a polymer sample drawn off of anindustrial process line. In general, the polymer sample may be obtainedafter the synthesis reaction is stopped or completed or during thecourse of the polymerization reaction. Alternatively, samples of eachpolymerization reaction can be taken and placed into an intermediatearray of vessels at various times during the course of the synthesis,optionally with addition of more solvent pr other reagents to arrest thesynthesis reaction or prepare the samples for analysis. Theseintermediate arrays can then be characterized at any time withoutinterrupting the synthesis reaction. It is also possible to use polymersamples or libraries of polymer samples that were prepared previouslyand stored. Typically, polymer libraries can be stored with agents toensure polymer integrity. Such storage agents include, for example,antioxidants or other agents effective for preventing cross-linking ofpolymer molecules during storage. Depending upon the polymerizationreaction, other processing steps may also be desired, all of which arepreferably automated. The polymerization scheme and/or mechanism bywhich the polymer molecules of the polymer component of the sample areprepared is not critical, and can include, for example, reactionsconsidered to be addition polymerization, condensation polymerization,step-growth polymerization, and/or chain-growth polymerizationreactions. Viewed from another aspect, the polymerization reaction canbe an emulsion polymerization or a dispersion polymerization reaction.Viewed more specifically with respect to the mechanism, thepolymerization reaction can be radical polymerization, ionicpolymerization (e.g., cationic polymerization, anionic polymerization),and/or ring-opening polymerization reactions, among others. Non-limitingexamples of the foregoing include, Ziegler-Natta or Kaminsky-Sinnreactions and various copolymerization reactions. Polymerization productmixtures can also be prepared by modification of a polymeric startingmaterials, by grafting reactions, chain extension, chain scission,functional group interconversion, or other reactions.

[0075] The sample size is not narrowly critical, and can generally vary,depending on the particular characterization protocols and systems usedto characterize the sample or components thereof. Typical sample sizescan range from about 0.1 μl to about 1 ml, more typically from about 1μl to about 1000 μl, even more typically from about 5 μl to about 100μl, and still more typically from about 10 μl to about 50 μl. Agenerally preferred sample size for flow characterization systems and,particularly for liquid chromatography, is a sample size of about 20 μl.

[0076] The polymer sample, such as a polymerization product mixture, canbe a raw, untreated polymer sample or can be pretreated in preparationfor characterization. Typical sample preparation steps includepreliminary, non-chromatographic separation of one or more components ofa polymer sample from other components, dilution, mixing and/orredissolution (e.g., from a solid state), among other operations.Preliminary separation methods can help remove large-scale impuritiessuch as dust, coagulum or other impurities. Such separation methods caninclude, for example: filtering (e.g., with a microfilter having poresizes that allow the passage of particles less than about 0.5 μm or 0.2μm); precipitation of polymer components, monomer components and/orother small-molecule components, decanting, washing, scavenging (e.g.,with drying agents), membrane separation (e.g., diafiltration,dialysis), evaporation of volatile components and/or ion-exchange. Thesample is preferably diluted, if necessary, to a concentration rangesuitable for detection. For typical liquid chromatography applications,for example, the sample concentration prior to loading into the liquidchromatography system can range from about 0.01 mg/ml to a neat sample,more typically from about 0.01 mg/ml to about 100 mg/ml, and even moretypically from about 0.1 mg/ml to about 50 mg/ml. More specificconcentration ranges typical for liquid chromatography samples includefrom about 0.1 mg/ml to about 20 mg/ml, and from about 0.5 mg/ml toabout 5 mg/ml. For flow-injection analysis systems, in which the sampleis detected without substantial chromatographic separation thereof, muchmore dilute solutions can be employed. Hence, the concentration canrange from a detectable concentration level (for the particular detectoremployed) up to about 1 mg/ml, or more in some applications. Typicalconcentrations can be about 1×10⁻² wt %, about 1×10⁻³ wt % or about1×10⁻⁴ wt %. Mixing can be required to increase the uniformity of apolymer sample emulsion or dispersion, and/or to integrate one or moreadditional components into the polymer sample. Preparation steps, andparticularly rapid preparation techniques, can be an important aspectfor combinatorial polymer investigations—since polymer samples may besynthesized in a form not ideally suited for immediate characterization.Pluralities of Polymer Samples/Libraries of Polymer Samples A pluralityof polymer samples comprises 2 or more polymer samples that arephysically or temporally separated from each other—for example, byresiding in different sample containers, by having a membrane or otherpartitioning material positioned between samples, by being partitioned(e.g., in-line) with an intervening fluid, by being temporally separatedin a flow process line (e.g., as sampled for process control purposes),or otherwise. The plurality of polymer samples preferably comprises 4 ormore polymer samples and more preferably 8 or more polymer samples. Fourpolymer samples can be employed, for example, in connection withexperiments having one control sample and three polymer samples varying(e.g., with respect to composition or process conditions as discussedabove) to be representative of a high, a medium and a low-value of thevaried factor—and thereby, to provide some indication as to trends. Fourpolymer samples are also a minimum number of samples to effect aserial-parallel characterization approach, as described above (e.g.,with two detectors operating in parallel). Eight polymer samples canprovide for additional variations in the explored factor space.Moreover, eight polymer samples corresponds to the number of parallelpolymerization reactors in the PPR-8™, being selectively offered as oneof the Discovery Tools™ of Symyx Technologies, Inc. (Santa Clara,Calif.). Higher numbers of polymer samples can be investigated,according to the methods of the invention, to provide additionalinsights into larger compositional and/or process space. In some cases,for example, the plurality of polymer samples can be 15 or more polymersamples, preferably 20 or more polymer samples, more preferably 40 ormore polymer samples and even more preferably 80 or more polymersamples. Such numbers can be loosely associated with standardconfigurations of other parallel reactor configurations (e.g., thePPR-48 , Symyx Technologies, Inc.) and/or of standard sample containers(e.g., 96-well microtiter plate-type formats). Moreover, even largernumbers of polymer samples can be characterized according to the methodsof the present invention for larger scale research endeavors. Hence, thenumber of polymer samples can be 150 or more, 400 or more, 500 or more,750 or more, 1,000 or more, 1,500 or more, 2,000 or more, 5,000 or moreand 10,000 or more polymer samples. As such, the number of polymersamples can range from about 2 polymer samples to about 10,000 polymersamples, and preferably from about 8 polymer samples to about 10,000polymer samples. In many applications, however, the number of polymersamples can range from about 80 polymer samples to about 1500 polymersamples. In some cases, in which processing of polymer samples usingtypical 96-well microtiter-plate formatting is convenient or otherwisedesirable, the number of polymer samples can be 96*N, where N is aninteger ranging from about 1 to about 100. For many applications, N cansuitably range from 1 to about 20, and in some cases, from 1 to about 5.

[0077] The plurality of polymer samples can be a library of polymersamples. A library of polymer samples comprises an array of two or moredifferent polymer samples spatially separated—preferably on a commonsubstrate, or temporally separated—for example, in a flow system.Candidate polymer samples (i.e., members) within a library may differ ina definable and typically predefined way, including with regard tochemical structure, processing (e.g., synthesis) history, mixtures ofinteracting components, purity, etc. The polymer samples are spatiallyseparated, preferably at an exposed surface of the substrate, such thatthe array of polymer samples are separately addressable forcharacterization thereof. The two or more different polymer samples canreside in sample containers formed as wells in a surface of thesubstrate. The number of polymer samples included within the library cangenerally be the same as the number of samples included within theplurality of samples, as discussed above. In general, however, not allof the polymer samples within a library of polymer samples need to bedifferent polymer samples. When process conditions are to be evaluated,the libraries may contain only one type of polymer sample. Typically,however, for combinatorial polymer science research applications, atleast two or more, preferably at least four or more, even morepreferably eight or more and, in many cases most, and allowably each ofthe plurality of polymer samples in a given library of polymer sampleswill be different from each other. Specifically, a different polymersample can be included within at least about 50%, preferably at least75%, preferably at least 80%, even more preferably at least 90%, stillmore preferably at least 95%, yet more preferably at least 98% and mostpreferably at least 99% of the polymer samples included in the samplelibrary. In some cases, all of the polymer samples in a library ofpolymer samples will be different from each other.

[0078] The substrate can be a structure having a rigid or semi-rigidsurface on which or into which the array of polymer samples can beformed or deposited. The substrate can be of any suitable material, andpreferably consists essentially of materials that are inert with respectto the polymer samples of interest. Certain materials will, therefore,be less desirably employed as a substrate material for certainpolymerization reaction process conditions (e.g., hightemperatures—especially temperatures greater than about 100° C.—or highpressures) and/or for certain reaction mechanisms. Stainless steel,silicon, including polycrystalline silicon, single-crystal silicon,sputtered silicon, and silica (SiO₂) in any of its forms (quartz, glass,etc.) are preferred substrate materials. Other known materials (e.g.,silicon nitride, silicon carbide, metal oxides (e.g., alumina), mixedmetal oxides, metal halides (e.g., magnesium chloride), minerals,zeolites, and ceramics) may also be suitable for a substrate material insome applications. Organic and inorganic polymers may also be suitablyemployed in some applications of the invention. Exemplary polymericmaterials that can be suitable as a substrate material in particularapplications include polyimides such as Kapton™, polypropylene,polytetrafluoroethylene (PTFE) and/or polyether etherketone (PEEK),among others. The substrate material is also preferably selected forsuitability in connection with known fabrication techniques. As to form,the sample containers formed in, at or on a substrate can be preferably,but are not necessarily, arranged in a substantially flat, substantiallyplanar surface of the substrate. The sample containers can be formed ina surface of the substrate as dimples, wells, raised regions, trenches,or the like. Non-conventional substate-based sample containers, such asrelatively flat surfaces having surface-modified regions (e.g.,selectively wettable regions) can also be employed. The overall sizeand/or shape of the substrate is not limiting to the invention. The sizeand shape can be chosen, however, to be compatible with commercialavailability, existing fabrication techniques, and/or with known orlater-developed automation techniques, including automated sampling andautomated substrate-handling devices. The substrate is also preferablysized to be portable by humans. The substrate can be thermallyinsulated, particularly for high-temperature and/or low-temperatureapplications. In preferred embodiments, the substrate is designed suchthat the individually addressable regions of the substrate can act aspolymerization reaction vessels for preparing a polymerization productmixture (as well as sample containers for the two or more differentpolymer samples during subsequent characterization thereof. Glass-lined,96-well, 384-well and 1536-well microtiter-type plates, fabricated fromstainless steel and/or aluminum, are preferred substrates for a libraryof polymer samples. The choice of an appropriate specific substratematerial and/or form for certain applications will be apparent to thoseof skill in the art in view of the guidance provided herein.

[0079] The library of polymer materials can be a combinatorial libraryof polymerization product mixtures. Polymer libraries can comprise, forexample, polymerization product mixtures resulting from polymerizationreactions that are varied with respect to, for example, reactantmaterials (e.g., monomers, comonomers), catalysts, catalyst precursors,initiators, additives, the relative amounts of such components, reactionconditions (e.g., temperature, pressure, reaction time) or any otherfactor affecting polymerization. Design variables for polymerizationreactions are well known in the art. See generally, Odian, Principles ofPolvmerization, 3^(rd) Ed., John Wiley & Sons, Inc. (1991). A library ofpolymer samples may be prepared in arrays, in parallel polymerizationreactors or in a serial fashion. Exemplary methods and apparatus forpreparing polymer libraries—based on combinatorial polymer synthesisapproaches—are disclosed in copending U.S. patent application Ser. No.09/211,982 of Turner et al. filed Dec. 14, 1998, copending U.S. patentapplication Ser. No. 09/227,558 of Turner et al. filed Jan. 8, 1999,copending U.S. patent application Ser. No. 09/235,368 of Weinberg et al.filed Jan. 21, 1999, and copending U.S. provisional patent applicationSer. No. 60/122,704 entitled “Controlled, Stable Free Radical Emulsionand Water-Based Polymerizations”, filed Mar. 9, 1999 by Klaerner et al.under Attorney Docket No. 99-4. See also, PCT Patent Application WO96/11878.

[0080] The libraries can be advantageously characterized directly,without being isolated, from the reaction vessel in which the polymerwas synthesized. Thus, reagents, catalysts or initiators and otheradditives for making polymers may be included with the polymer samplefor characterization or screening.

[0081] While such methods are preferred for a combinatorial approach topolymer science research, they are to be considered exemplary andnon-limiting. As noted above, the particular polymer samplescharacterized according to the methods and with the apparatus disclosedherein can be from any source, including, but not limited topolymerization product mixtures resulting from combinatorially synthesisapproaches.

[0082] Non-polymer Samples

[0083] Although the primary applications of the present invention aredirected to combinatorial polymer science research and/or qualitycontrol for industrial polymer synthesis or processing protocols, someaspects of the invention can have applications involving non-polymersamples. A non-polymer sample can be a material that comprises anorganic or an inorganic non-polymer element or compound. Oligomers areconsidered to be polymers rather than non-polymers. The non-polymermolecule is, in some cases, preferably a non-biological non-polymerelement or compound. Such non-biological non-polymer elements orcompounds include non-polymer elements or compounds other than thosehaving a well-characterized biological activity and/or a primarycommercial application for a biological field (e.g., steroids, hormones,etc.). More particularly, such non-biological, non-polymer elements orcompounds can include organic or inorganic pigments, carbon powders(e.g., carbon black), metals, metal oxides, metal salts, metal colloids,metal ligands, etc, without particular limitation.

[0084] Detectors/Detected Properties/Determined Properties

[0085] A polymer sample is characterized by detecting a property of thepolymer sample, or by detecting a property of a component (e.g., apolymer component, a monomer component) of the polymer sample. In manycases, the property is detected over a period of time, such that avariation in the property can be observed or detected or the rate ofchange of variation of a property can be observed or detected. In thegeneral case, the detected property can be any property which canprovide a scientifically meaningful basis of comparison between twodifferent polymer samples or between two different polymercomponents—either directly, or after being correlated to a specificcharacterizing property of interest. The detected property can be achemical property or a physical property of the polymer sample orcomponent thereof. In preferred applications, an optical property of thepolymer sample or a component thereof can be detected. For example, anamount, frequency, intensity or direction of an incident light that isrefracted, scattered, and/or absorbed by the polymer sample or acomponent thereof may be detected. Other properties, such as pressure orother factors affecting a particular characterizing property of interest(e.g., viscosity) can likewise be detected.

[0086] With reference to FIGS. 2A and 2B (discussed in greater detailbelow), a property of a polymer sample or of a component thereof, suchas a chromatographically separated component thereof, can be detected ina flow characterization system with one or more detectors 130. Inpreferred embodiments, a property of a polymer sample or of a componentthereof is detected with an optical detector such as a refractive-indexdetector, an ultraviolet-visual detector, a photodiode array detector, astatic-light-scattering detector, a dynamic-light-scattering detector,and/or an evaporative-light-scattering detector—also known as anevaporative mass detector (EMD). Other detectors (e.g., a capillaryviscometer detector, photodiode array detector (PDAD), infra-reddetector, fluorescence detector, electrochemical detector, conductivitydetector, etc.) can likewise be employed in connection with the presentinvention. The particular nature of the detector (e.g., shape and/orconfiguration of a detection cavity 131 within the detector) is notgenerally critical.

[0087] The protocols for characterizing one or more polymer samplespreferably further comprise determining a property of interest from thedetected property. The physically-detected properties, such as thecapability of the polymer sample or component thereof to refract,scatter, emit or absorb light can be correlated to properties ofinterest. Such properties of interest include, without limitation,weight-average molecular weight, number-average molecular weight,viscosity-average molecular weight, peak molecular weight, approximatemolecular weight, polydispersity index, molecular-weight-distributionshape, relative or absolute component concentration, chemicalcomposition, conversion, concentration, mass, hydrodynamic radius(R_(h)), radius of gyration (R_(g)), chemical composition, amounts ofresidual monomer, presence and amounts of other low-molecular weightimpurities in polymer samples, particle or molecular size, intrinsicviscosity, molecular shape, molecular conformation, and/or agglomerationor assemblage of molecules. The correlation between a detected propertyand a determined property of interest can be based on mathematicalmodels and/or empirical calibrations. Such correlation methods aregenerally known in the art, and are typically incorporated intocommercially-available chromatographic detectors and/or detector ordata-acquisition software.

[0088] For combinatorial polymer science research applications, as wellas other applications, the characterization protocols can be effected todetermine at least a weight-average molecular weight as acharacterization property of primary importance. Other characterizationproperties of interest of substantial importance, include number-averagemolecular weight, polydispersity index, andmolecular-weight-distribution shape. For polymer samples that arepolymerization product mixtures, another characterization property ofsubstantial importance is conversion data for the polymerizationreaction, typically expressed as % monomer converted into polymer. Thecomposition of the polymer sample or of particular components thereof(e.g., polymer components) can also be of substantial importance.

[0089] For determining weight-average molecular weight from detectedproperties, a liquid chromatography system or a flow-injection analysissystem can advantageously employ a single detector or a combination oftwo or more detectors. In a single-detector embodiment, for example, adynamic light-scattering (DLS) detector can be used by itself todetermine an average hydrodynamic radius or a distribution ofhydrodynamic radii from the detected scattered light. The hydrodynamicradii can, in turn, be correlated to an average molecular weight or amolecular weight distribution. In a two-detector embodiment, forexample, a static-light scattering (SLS) detector (where the detectedscattered light is a function of weight-average molecular weight (Mw),concentration (C) and the square of the refractive index increment,(dn/dC)²) can be combined with a refractive index (RI) detector (wherethe detected refracted light is a function of (C) and (dn/dC)), with anultraviolet/visible light absorbance (UV/VIS) detector (where thedetected absorbed light is a function of (C)), or with an evaporativelight scattering detector (ELSD) (where the detected scattered light isa function of (C)). In another embodiment, a single-detector or multipledetectors (e.g., SLS) can detect the intensity of light scattered by thesample or sample component at two or more different angles, which can becorrelated to molecular weight.

[0090] For polymer samples that are polymerization product mixtures,conversion data for the polymerization reaction of which the sample isrepresentative can be determined by chromatographically resolving thepolymer component(s) and monomer component(s), determining amolecular-weight distribution for such components, integrating areasunder the respective peaks, and then comparing the integrated peak areas(e.g., using response factors for particular components and detectoremployed). Another approach for calculating conversion involvesconverting the polymer-peak area into polymer concentration or massusing a concentration-detector response calibration plot, and thencomparing the portion of the polymer mass or concentration found in thesample to the expected mass or concentration assuming 100%stoichiometric conversion.

[0091] Composition data for a polymer sample can be determined from theconsumption of monomer or comonomers or, alternatively, from a retentiontime per volume of the polymer peak or a fraction thereof.

[0092] Advantageously, an ELSD detector, or other detectors that are notparticularly sensitive to low-molecular weight components of a polymersample, can be advantageously employed in connection with the flowcharacterization protocols of the invention to achieve a highsample-throughput. As discussed in greater detail below, detectors thatare insensitive to low-molecular weight components can be advantageouslyemployed in connection with rapid-serial overlapping techniques.Moreover, because the ELSD is also less sensitive to temperaturevariations than other types of mass detectors (e.g., RI detector) and isnot required to be in thermal equilibrium with the sample beingdetected, an ELSD detector can be employed advantageously in connectionwith high-temperature polymer characterization systems. Hence, detectinga property of a polymer sample or a component there of with an ELSD orwith other low-MW insensitive or less temperature sensitive massdetectors provides a further aspect for improving the samplethroughput—particularly for a liquid chromatography system 10 or aflow-injection analysis system 20.

[0093] The aforementioned characterizing properties of interest can,once determined, be mathematically combined in various combinations toprovide figures of merit for various properties or attributes ofinterest. In particular, for example, molecular weight, conversion andpolydispersity index can be evaluated versus polymerization process timeto provide mechanistic insights as to how polymers are formed. Othercombinations of the fundamental characterization properties of interestwill be apparent to those of skill in the art.

[0094] Specific applications and/or combinations of detectors, as wellas correlation protocols, are discussed in greater detail below

[0095] Sample—Throughput

[0096] For methods directed to characterizing a plurality of samples, aproperty of each of the samples or of one or more components thereof isdetected—serially or in a parallel, serial-parallel or hybridparallel-serial manner—at an average sample throughput of not more thanabout 10 minutes per sample. As used in connection herewith, the term“average sample throughput” refers to the sample-number normalized total(cumulative) period of time required to detect a property of two or morepolymer samples with a characterization system. The total, cumulativetime period is delineated from the initiation of the characterizationprocess for the first sample, to the detection of a property of the lastsample or of a component thereof, and includes any interveningbetween-sample pauses in the process. The sample throughput is morepreferably not more than about 8 minutes per sample, even morepreferably not more than about 4 minutes per sample and still morepreferably not more than about 2 minutes per sample. Depending on thequality resolution of the characterizing information required, theaverage sample throughput can be not more than about 1 minute persample, and if desired, not more than about 30 seconds per sample, notmore than about 20 seconds per sample or not more than about 10 secondsper sample, and in some applications, not more than about 5 seconds persample and not more than about 1 second per sample. Sample-throughputvalues of less than 4 minutes, less than 2 minutes, less than 1 minute,less than 30 seconds, less than 20 seconds and less than 10 seconds aredemonstrated in the examples. The average sample-throughput preferablyranges from about 10 minutes per sample to about 10 seconds per sample,more preferably from about 8 minutes per sample to about 10 seconds persample, even more preferably from about 4 minutes per sample to about 10seconds per sample and, in some applications, most preferably from about2 minutes per sample to about 10 seconds per sample.

[0097] A sample-throughput of 10 minutes per sample or less is importantfor a number of reasons. Flow-characterization systems that detect aproperty of a polymer sample or of a component thereof at theaforementioned sample throughput rates can be employed effectively in acombinatorial polymer research program. From a completely practicalpoint of view, the characterization rates are roughly commensurate withreasonably-scaled polymer sample library synthesis rates. It isgenerally desirable that combinatorial screening systems, such as thepolymer characterization protocols disclosed herein, operate withroughly the same sample throughput as combinatorial synthesisprotocols—to prevent a backlog of uncharacterized polymerization productsamples. Hence, because moderate scale polymer-synthesis systems, suchas the Discovery Tools™ PPR-48™ (Symyx Technologies, Santa ClaraCalif.), can readily prepare polymer libraries with a sample-throughputof about 100 polymer samples per day, a screening throughput of about 10minutes per sample or faster is desirable. Higher throughput synthesissystems demand higher characterization throughputs. The preferred higherthroughput values are also important with respect to process controlapplications, to provide near-real time control data. It is possible,moreover, that a particular sample being characterized may includecomponent that are themselves different analytes of interest, such thatthe per-analyte throughput for the characterization system can besignificantly higher than the per-sample throughput thereof.

[0098] Additionally, as shown in connection with the examples providedherein, the characterization of polymer samples at such throughputs canoffer sufficiently rigorous quality of data, especially weight-averagemolecular weight, to be useful for scientifically meaningful explorationof the polymer compositional and/or polymerization reaction conditionsresearch space. Specifically, at sample throughputs ranging from about10 minutes per sample to about 8 minutes per sample, the polymer sampleor one or more components thereof can be characterized with respect toweight-average molecular weight, number-average molecular weight,polydispersity index, molecular weight distribution shape, andconversion information—all at reasonably high quality resolution. At asample throughput ranging between about 8 minutes per sample to about 2minutes per sample, the polymer sample or one or more components thereofcan be characterized with respect to weight-average molecular weight—atreasonably high quality resolution, and with respect to number-averagemolecular weight, polydispersity index, molecular weight distributionshape, and conversion information—all with good quality resolution. SeeExample 17. At a sample throughput ranging between about 2 minutes persample to about 1 minute per sample, the polymer sample or one or morecomponents thereof can be characterized with respect to weight-averagemolecular weight and conversion information—at reasonably high qualityresolution, and with respect to number-average molecular weight,polydispersity index, and molecular weight distribution shape—all withmoderate quality resolution. See Example 16. At a sample throughputranging between about 1 minute per sample to about 30 seconds persample, the polymer sample or one or more components thereof can becharacterized with respect to weight-average molecular weight—withmoderate quality resolution. See Example 15.

[0099] Hence, the average sample-throughput can range, in preferredcases, from about 10 minutes per sample to about 8 minutes per sample,from about 8 minutes per sample to about 2 minutes per sample, fromabout 2 minutes per sample to about 1 minute per sample, from about 1minute per sample to about 30 seconds per sample and from about 1 minuteper sample to about 10 seconds per sample, with preferences depending onthe quality of resolution required in a particular case. For example, insome research strategies, the very high sample throughputs can beeffectively employed to efficiently identify a polymer sample orcomponent thereof having a particularly desired property (e.g., such asweight-average molecular weight). In short, the search can beaccelerated for the particular property of research interest.

[0100] Specific protocols, systems and devices for achieving theaforementioned average sample throughput values for a plurality ofpolymer samples are discussed and exemplified in greater detail below.

[0101] Flow Characterization Systems

[0102] In a preferred approach, a plurality of polymer samples arecharacterized by serially detecting a property of a plurality of polymersamples or of components thereof in a flow characterization system, suchas a liquid chromatography system or a related, flow-injection analysissystem, at an average sample-throughput of not more than about 10minutes per sample. Unlike traditional flow characterization protocols,which are designed to achieve universality with respect to polymer typeand with respect to quality of information—without substantial concernfor sample throughput, the high-throughput protocols disclosed andclaimed herein achieve high sample throughput, while optimizing qualityand universality to the extent necessary for the particular application.Rapid characterization for individual samples and/or for a plurality ofsamples are achieved, in general, by improving the efficiency ofsampling (polymer sample withdrawal, preparation, and delivery),chromatographic separation (for liquid chromatography systems) anddetection. As such, the protocols of the invention can be advantageouslyemployed, inter alia, for combinatorial polymer research and/or for nearreal time process control applications.

[0103] Liquid Chromatography Systems/Flow-Injection AnalysisSystems—Overview

[0104] The polymer samples are preferably characterized according to themethods of the present invention with a flow characterization system. Asused herein, the term “flow characterization system” refers to a polymercharacterization system in which a polymer sample flows into a detectioncavity of a flow-through detector, a property of the polymer sample orof a component thereof is detected while the sample (or a portionthereof) resides in the detection cavity, and the polymer sample flowsout of the detection cavity. The flow-through detector can also beinterchangeably referred to as a continuous-flow detector. Aflow-through detector may have more than one detection cavity, and theflow characterization system may have more than one flow-throughdetector. As referred to herein, an individual flow-characterizationsystem has a single common flow path, as delineated by a common point ofsample injection (typically, through an injection valve) to a commonpoint of sample exhaust (typically, through a sample effluent port, andusually leading to a waste collection container). The flow path of anindividual flow-characterization system may, nonetheless, splitinternally within the system (e.g., with a flow-through detector havingmultiple detection cavities—such as with capillary-type detectioncavities.

[0105] Flow characterization systems can be broadly classified, forpurposes of the present invention, as liquid chromatography systems andflow-injection analysis systems. Liquid chromatography systems are flowcharacterization systems that effect at least some chromatographicseparation of a polymer sample prior to detection of the sample or ofcomponents thereof in a flow-through detector. Flow-injection analysissystems are flow characterization systems without substantialchromatographic separation of the sample prior to detection with theflow-through detector. Flow-injection analysis systems can, however,include apparatus for non-chromatographic separations (e.g.,filtration). Moreover, a polymer sample can be prepared, prior toflow-injection analysis (or prior to liquid chromatography), byseparating one or more components of the raw sample from othercomponents thereof.

[0106] Briefly, with reference to FIG. 2A, a liquid chromatographysystem 10 comprises an injection valve 100 (sometimes referred to as aninjection loop) having an injection port 108, a chromatographic column102, a flow-through detector 130, and an effluent port 141. An in-linefilter 104, additional injection ports 108′, additional chromatographiccolumns 102 and/or additional flow-through detectors 130 can also beincluded in the system 10. Additionally, switches (e.g., automatedswitches) can be included to switch between various options with respectto filters 104, columns 102, detectors 130. In operation, a mobile-phasefluid is pumped from a mobile-phase reservoir 114 by pump 116 throughthe injection valve 100, chromatographic column 102 and detector 130.The pump 116 can be controlled with a microprocessor 134. The mobilephase can be exhausted from the system via effluent port 141 into awaste collection container 140. A polymer sample is loaded into theinjection valve 100 through the injection port 108, and the loadedsample is injected into the mobile phase of the chromatographic system.The injected sample is chromatographically separated in thechromatographic column 102. A property of the polymer sample, and/or ofone or more separated components thereof, is then detected while thesample resides in a detection cavity 131 of the detector 130. Amicroprocessor (e.g., computer) 134 is typically in electroniccommunication with the detector to collect, process and analyze the dataobtained therefrom. While the same microprocessor 134 is shown in thefigure for pump 116 control and data acquisition, these functions couldbe effected with separate microprocessors 134.

[0107] With reference to FIG. 2B, a flow-injection analysis system 20can comprise an injection valve 100 having an injection port 108, aflow-through detector 130 and an effluent port 141. The flow-injectionanalysis system can also include an in-line filter 104, and can haveadditional injection ports 108 and/or flow-through detectors 130. Inoperation, a mobile-phase fluid is pumped from a mobile-phase reservoir114 by pump 116 through the injection valve 100, filter 104 (if present)and detector 130. The pump 116 can be controlled with a microprocessor134. The mobile phase can be exhausted from the system via effluent port141 into to a waste collection container 140. A polymer sample is loadedinto the injection valve 100 through the injection port 108, and theloaded sample is injected into the mobile phase of the flow-injectionanalysis system. The injected sample is optionally filtered in thefilter 104, and then a property of the polymer sample, and/or ofcomponents thereof, is then detected while the sample resides in adetection cavity 131 of the detector 130. A microprocessor (e.g.,computer) 134 is typically in electronic communication with the detectorto collect and analyze the data obtained therefrom. Although the samemicroprocessor 134 is shown in the figure for pump 116 control and dataacquisition, these functions could be effected with separatemicroprocessors 134.

[0108] The components of the liquid chromatography system 10 and theflow-injection-analysis system 20 are described more specifically below.The description of components common for each of the systems 10, 20(e.g., injection valves 100) are applicable to each such system, unlessspecifically designated otherwise in the context of particularlydescribed embodiments.

[0109] Reservoir/Pumps

[0110] Referring again to FIGS. 2A and 2B, the reservoir 114 of a flowcharacterization system can be of any suitable design and capacity, andtypically has a volume of about 4 liters. The particular mobile-phasefluid to be included in the reservoir 114 for the flow characterizationsystem can be selected in view of the polymer sample, detector, desiredflowrates, and liquid chromatography systems, further in view of thechromatographic separation technique being employed. Exemplarymobile-phase fluids for liquid chromatography systems (e.g., GPC,precipitation-redissolution chromatography, adsorption chromatographyand reverse-phase chromatography) and for flow-injection analysissystems are discussed below. The pump 116 can be of any type and sizesuitable to provide a motive force for the mobile-phase fluid throughthe flow-characterization systems 10, 20. Typical high-pressure liquidchromatography pumps, available commercially from various sources, suchas Waters Model No. 515 (Milford, Mass.) can be employed. The flowcharacterization systems 10, 20 can include additional reservoirs 114,and additional pumps 116 to provide more than one mobile-phase fluid, toprovide a mobile-phase composition gradient or, as discussed below, toprovide a mobile-phase temperature gradient. Injection Valve Theinjection valve 100 comprises one or more injection ports 108, one ormore sample loops, one or more mobile-phase inlet ports 101, and one ormore mobile-phase outlet ports 103. The polymer sample can be injecteddirectly through an injection port 108 into the mobile phase flowingthrough the injection valve 100. In preferred embodiments, however, theinjection valve 100 is an injection port valve typical of those used fora high pressure liquid chromatography system. As used in this context,and with application to both liquid chromatography systems 10 of theinvention and flow-injection analysis systems 20 of the invention, “highpressure” refers to internal system pressures (e.g., mobile-phasepressures) above atmospheric pressure, typically ranging from about 0psig to about 6000 psig, preferably from about 10 psig to about 4000psig, and more typically from about 100 psig to about 2000 psig.

[0111] With reference to FIG. 3, the injection valve 100 can be an8-port injection port valve 210 (100) that operates as follows. Numeralsin parenthesis refer to corresponding parts of the injection valve ofFIGS. 2A and 2B. A first polymer sample is loaded directly into aninjection port 108 or indirectly through a loading port 204, transferline 206 and the injection port 108 at relatively low pressure comparedto the pressure of the mobile phase. The loading port 204 can be adaptedin size to accommodate one or more injection probes (tips) of a manualor an automated sample delivery unit (e.g., an auto-sampler). When the8-ported valve is in valve position “A” (with internal flow-paths forthe valve indicated by solid lines), the first polymer sample is loadedinto a sample loop 205A while the mobile phase flows through the valvevia mobile-phase inlet port 101 (the flow-in port), sample loop 205B,and mobile-phase outlet port 103 (the flow-out port). The sample loops205A and 205B can be of equal volume. A waste port 207 can be employedfor receiving any overflow sample and/or for flushing the valve aftereach sample, if necessary. When the injection valve 210 is switched tothe valve “B” position (with internal flow-paths for the valve nowindicated by the dashed lines), the mobile phase then flows through thevalve via mobile-phase inlet port 100, sample loop 205A, andmobile-phase outlet port 103, and the first polymer sample is therebyinjected into the mobile phase of the liquid chromatography system 10 orflow-injection analysis system 20. While the first polymer sample isbeing injected from sample loop 205A into the mobile phase of the flowcharacterization system, a second polymer sample can be loaded intosample loop 205B, ready to be injected once the valve is switched backto valve position A. Eight-ported valves, such as represented in FIG. 3,can be purchased from Valco Instruments Co. Inc. (Houston, Tex.), andthe purchased valve fittings can be modified as described above for usein connection with a flow characterization system. An eight portinjection valve 210 is a preferred injection valve 100 because the twosample loops 205A, 205B allow the flow characterization system to beready for sample loading at all times (i.e., has a load/loadcapability). As such, the eight-port valve is faster than, for example,a six port valve (e.g., a valve having only a single load position and asingle inject position), and therefore, the eight-port injection valveprovides one aspect for improving the sample throughput for a liquidchromatography system 10 or a flow-injection analysis system 20. Whilethe eight-port valve 210 depicted schematically in FIG. 3 is a preferredconfiguration, other high-pressure injection valves can also be suitablyemployed, including, without limitation, valves having a greater orlesser number of ports. Typically, however, a high-pressure injectionvalve will have from 6 to 24 ports.

[0112] Referring to FIG. 2A, FIG. 2B and FIG. 3, the injection valve 100(210) can be configured to have more than one injection port 108, 108′or a single injection port 108, and in either case, the single ormultiple injection ports 108, 108′ can be in fluid communication with anumber of loading ports 204 via a number of transfer lines 206 in orderto receive polymer samples independently from a number of differentinjection probes, including, for example, a manual injection probes, andone or more probes associated with automated delivery systems, such asone or more robotic auto-samplers. The injection valve can also have alarger number of sample loops with the same or with varying volumes, toaccommodate different samples sizes.

[0113] Sampling/Auto-sampler

[0114] Sampling of a polymer sample refers to a plurality of steps whichinclude withdrawing a polymer sample from a sample container anddelivering at least a portion of the withdrawn sample to a polymercharacterization system. Sampling may also include additional steps,particularly and preferably, sample preparation steps. (See FIG. 1A). Inone approach, only one polymer sample is withdrawn into the auto-samplerprobe at a time and only one polymer sample resides in the probe at onetime. The one polymer sample is expelled therefrom (for samplepreparation and/or into the polymer characterization system) beforedrawing the next polymer sample. In an alternative approach, however,two or more polymer samples can be withdrawn into the auto-sampler probesequentially, spatially separated by a solvent, such that the two ormore polymer samples reside in the probe at the same time. Such a“candystriping” approach can provide for very high auto-samplerthroughputs for rapid introduction of the one or more samples into theflow characterization system.

[0115] The sample container from which the polymer sample is withdrawnis not critical. The sample container can be, for example asample-containing well. The sample-containing well can be a sample vial,a plurality of sample vials, or a sample-containing well within an arrayof sample-containing wells (e.g., constituting a polymer samplelibrary). The sample container can alternatively be a sample port from asample line in fluid communication with an industrial process line, suchas a polymerization process line.

[0116] In the general case, sampling can be effected manually, in asemi-automatic manner or in an automatic manner. A polymer sample can bewithdrawn from a sample container manually, for example, with a pipetteor with a syringe-type manual probe, and then manually delivered to aloading port or an injection port of a polymer characterization system.In a semi-automatic protocol, some aspect of the protocol is effectedautomatically (e.g., delivery), but some other aspect requires manualintervention (e.g., withdrawal of polymer samples from a process controlline). Preferably, however, the polymer sample(s) are withdrawn from asample container and delivered to the characterization system in a fullyautomated manner—for example, with an auto-sampler.

[0117] A plurality of polymer samples, such as those included within alibrary of polymer samples, is preferably delivered to the injectionvalve 100, for loading into the flow characterization system, with anautomatic delivery device, such as an auto-sampler. As used herein, theterm “auto-sampler” refers to an apparatus suitable for automatedsampling of polymer samples for characterization, including automatedwithdrawal of a polymer sample from a sample container, and automatedloading of at least a portion of the withdrawn sample into an injectionport or a loading port of a flow characterization system (e.g. a liquidchromatography system).

[0118] Automated sampling equipment is available commercially forintroducing multiple samples into liquid flow systems in a serialmanner. While such commercially-available auto-sampling equipment couldbe used with this invention, currently available systems have severaldrawbacks. First, commercially available auto-samplers typically operatewith a single predefined rack or tray configuration, which containsvials in a rectangular, linear, or rotary array. Samples are loadedmanually and individually into vials, and manually placed in the arrayfor subsequent sampling. The combinatorial aspects of this invention,however, prefer automated sample preparation of vast numbers of samples,from a variety of parallel vessel arrays or reactor blocks.Additionally, commercial auto-sampling equipment is not sufficientlyrapid. Conventional auto-samplers require up to several minutes percycle to introduce a polymer sample into a flow characterizationsystem—including steps such as sample changing, drawing, loading, andcleaning of the system in preparation for the next sample. (Seecomparative Ex. 1). For the purposes of this invention, more rapidsample introduction is desirable—preferably requiring much less than oneminute per sample. Moreover, conventional commercially-availableauto-sampling equipment is not designed for complex sample preparation,including transfer, dilution, purification, precipitation, or othersteps needed to prepare elements of a combinatorial array forcharacterization.

[0119] As such, aspects of this invention are directed to anauto-sampler and auto-sampling methods. In a preferred embodiment, withreference to FIG. 4, an auto-sampler 200 can comprise a movable probe(tip) 201, typically mounted on a support arm 203, a translation station221 for providing three-dimensional motion of the probe, and amicroprocessor 222 for controlling three-dimensional motion of the probebetween various spatial addresses. The auto-sampler 200 preferably alsocomprises a user-interface (not shown) to allow for user programming ofthe microprocessor 222 with respect to probe motion and manipulations.The probe 201 can have an interior surface defining a sample-cavity andan inlet port for fluid communication between the sample cavity and apolymer sample 20. The probe 201 is also adapted for fluid communicationwith an injection port 108 (FIG. 2A, FIG. 2B) or a loading port 204 of aflow characterization system. The support arm 203 is preferably an XYZrobotic arm, such as can be commercially obtained from Cavro ScientificInstruments, Inc. (Sunnyvale, Calif.) among others. To improvesmoothness of operation at high speeds, such XYZ robotic arms preferablyhave motions based on gradient variations rather than step-functionvariations, and preferably are belt-driven rather than shaft driven. Themicroprocessor 222 can be a computer and can be the same or differentfrom the microprocessor 134 (FIG. 2A, FIG. 2B) used to control thedetectors 130 (FIG. 2A, FIG. 2B) and data acquisition therefrom. Theauto-sampler can further comprise one or more pumps (not shown),preferably syringe pumps, for drawing and/or expelling liquids, andrelated connection lines (not shown) for fluid communication between thepumps, the probe 201, and liquid (e.g. solvent) reservoirs. Preferredembodiments include two or more syringe pumps—one with a relativelylower flowrate capacity and one with a relatively higher flowratecapacity. (See Ex. 1). Alternative pump configurations, such asperistaltic pumps, vacuum-pumps or other motive-force providing meanscan be used additionally or alternatively. Sampling throughputs may alsobe enhanced by using two or more robotic arms together (See Ex. 2). Itis likewise possible to have more two or more sample probes inconnection with a single robotic arm—for example, such as an array oftwo or more probes each capable of synchronized motion relative to eachother.

[0120] In operation, the microprocessor 222 of the auto-sampler 200 canbe programmed to direct the auto-sampler 200 to withdraw a polymersample 20 (e.g., a polymer solution comprising a dissolved polymer) froma sample container (e.g., a sample well) formed in a sample tray 202into the injection probe 201, and subsequently to direct the probe 201to the loading port 204 for loading the sample into the characterizationsystem through transfer line 206. In preferred embodiments, theauto-sampler can be programmed to automatically sample each well of alibrary of polymer samples one after the other whereby a plurality ofpolymer samples are serially loaded into the flow characterizationsystem, and subsequently serially injected into the mobile phase of thecharacterization system in a plug flow fashion. Preferably, themicroprocessor 222 of the auto-sampler comprises a user-interface thatcan be programmed to allow for variations from a normal sampling routine(e.g., skipping certain elements at certain spatial addresses of alibrary). The auto-sampler 200 can also be controlled for manualoperation on an individual sample by sample basis.

[0121] The microprocessor 222 is also preferably user-programmable toaccommodate libraries of polymer samples having varying arrangements ofarrays of polymer samples (e.g., square arrays with “n-rows” by“n-columns”, rectangular arrays with “n-rows” by “m-columns”, roundarrays, triangular arrays with “r-” by “r-” by “r-” equilateral sides,triangular arrays with “r-base” by “s-” by “s-” isosceles sides, etc.,where n, m, r, and s are integers). More particularly, for example, withrespect to square or rectangular arrays, a two sets of samples (e.g.,libraries) having different spatial configurations can be sampled asfollows. First, an auto-sampler is programmed (e.g., via a userinterface module) with location information for a first set of samplescomprising a plurality of samples in a plurality of sample containers infirst spatial arrangement (e.g., “n-rows” by “m-columns”, where n and mare integers). The first set of samples are serially withdrawn fromtheir respective sample containers, and at least a portion of each ofthe withdrawn first set of samples are serially delivered to one or moreintended locations (e.g., a characterization system). The auto-sampleris then reprogrammed with location information for a second set ofliquid samples that comprise a plurality of samples in a plurality ofsample containers in second spatial arrangement (e.g., “p-rows” by“q-columns”, where p and q are integers). The second set of samples areserially withdrawn from their respective sample containers, and at leasta portion of each of the withdrawn second set of samples are seriallydelivered to one or more intended locations.

[0122] In a preferred protocol for sampling a plurality of polymersamples, an auto-sampler provides for rapid-serial loading of theplurality of polymer samples into a common injection port of aninjection valve. More specifically, a plurality of polymer samples issampled as follows. At a first withdrawal time, t_(ASW1), a firstpolymer sample is withdrawn from a first sample container at a firstlocation into a probe of an auto-sampler. At least a portion of thewithdrawn first sample is then delivered to an injection port of apolymer characterization system, either directly, or through a loadingport and a transfer line. After delivery of the first polymer sample, asecond polymer sample is, at a second withdrawal time, t_(ASW2),withdrawn from a second sample container at a second location into theauto-sampler probe. At least a portion of the withdrawn second sample isthen delivered (directly or indirectly) to the injection port of thepolymer characterization system. The auto-sampler cycle time, T_(AS),delineated by the difference in time, t_(ASW2)−t_(ASW1), is preferablynot more than about 40 seconds, more preferably not more than about 30seconds, even more preferably not more than about 20 seconds, morepreferably still not more than about 10 seconds, and most preferably notmore than about 8 seconds. The cycle can then be repeated, as necessary,in an automated manner, for additional polymer samples included withinthe plurality of polymer samples. The operation of the auto-sampler insuch a high-speed, rapid-serial manner provides another aspect forimproving the sample throughput for a liquid chromatography system 10 ora flow-injection analysis system 20.

[0123] The preferred protocol for sampling a plurality of polymersamples can also include additional automated steps. Preferably forexample, in an interval of the sampling cycle defined by the period oftime after delivery of at least a portion of the first polymer sampleinto a loading port or an injection port of a flow characterizationsystem, and before withdrawal of the second polymer sample, a residualportion of the first sample still remaining in the sample cavity of theauto-sampler probe, if any, can be expelled therefrom, for example to awaste container. Additionally or alternatively, the auto-sampler probecan be cleaned during this interval of the sampling cycle. Cleaning theauto-sampler probe, in an automated fashion, can include flushing thesample cavity of the probe with a solvent source available to the probe,and then expelling the solvent into a waste container. Such withdrawaland expelling of a cleaning solvent can be repeated one or more times,as necessary to effectively limit the extent of cross-contaminationbetween the first and second polymer samples to a level that isacceptable. As an alternative or additional cleaning protocol, the probemay be immersed in a cleaning solution and moved around therein toeffectively rinse residual polymer sample from both the external portionof the probe and the sample cavity thereof. The expelling step and theone or more cleaning steps can be, and are preferably automated. Whileexpelling and cleaning steps are generally preferred, no cleaning may berequired for polymer characterization applications in which minor samplecross-contamination is acceptable for a rough characterization of thepolymer samples. The expelling and one or more cleaning steps can beeffected within the preferred sampling cycle times recited above.

[0124] Sample preparation steps can also be included in the preferredprotocol for sampling a plurality of polymer samples. The samplepreparation steps, examples of which are discussed more specificallybelow, are preferably automated, preferably effected with theauto-sampler, and are preferably effected within the preferred samplecycling times recited above.

[0125] Significantly, sample preparation steps (also referred to hereinas pretreatment steps) for a plurality of samples are preferablyintegrated into a rapid-serial sampling approach such that each of theprepared samples is loaded into the polymer characterization system, andsubsequently characterized shortly after the sample-preparation stepsare completed. In preferred protocols, for example, the prepared samplesare injected into a mobile phase of polymer characterization systemwithin not more than about 30 seconds, more preferably not more thanabout 20 seconds, still more preferably not more than about 10 seconds,even more preferably not more than about 8 seconds, and most preferablynot more than about 5 seconds after preparation steps are complete. Thisapproach is unlike typical automated preparation protocols—developedprimarily for liquid samples other than the preferred non-biologicalpolymer samples. In known approaches, an entire plurality of liquidsamples is typically prepared before any of the plurality of liquidsamples is delivered to a characterization system. Although the knownconventional approach may be satisfactory for aqueous-based,non-volatile systems, such an approach is generally less preferred forcharacterizing polymer samples, which may include a volatileliquid-phase component or are worked up with preparation steps thatinclude volatile solvents. If the conventional approaches were appliedto a larger plurality (e.g. a number greater than about 8 polymersamples) of polymer samples having a volatile liquid-phase component,the time during which the prepared samples await delivery to the flowcharacterization system can result in a change in constituentconcentrations and, therefore, can effect the comparative basis betweendetected properties of different polymer samples. As an alternativeapproach, where parallel sample preparation is necessary or desired andthe sample may be stored for some period of time (e.g., more than about1 hour), it may be desirable to cover the sample containers having theprepared samples to minimize evaporation and protect againstcontamination (e.g., by dust). Preferably, the containers can be coveredwith a physically weak, chemically inert barrier such as Teflon™ tape,that can be pierced by the probe for sample withdrawal, thereby allowingneighboring covered samples to remain covered until immediately prior tosampling. As yet another alternative, for samples that may have lostsome of the solvent due to evaporation thereof, the solvent can bereplenished to a desired level immediately prior to loading of thesample into the characterization system.

[0126] Hence, a plurality of polymer samples, especially 8 or morepolymer samples, are preferably sampled in a rapid-serial manner bydrawing at least a portion of a polymer sample from a sample containerinto a probe of an auto-sampler, expelling at least a portion of thedrawn sample to a sample-preparation container, pretreating the expelledsample in the sample-preparation container to form a pretreated sample,drawing at least a portion of the pretreated sample from thesample-preparation container into the auto-sampler probe, delivering atleast a portion of the pretreated sample mixture to a polymercharacterization system, and then serially repeating each of theimmediately-aforementioned steps for the plurality of polymer samples.In preferred protocols, such steps are effected within the samplingcycle times discussed above. Such rapid-serialwithdrawal-preparation-delivery protocols are advantageous over priorart protocols, and as applied to a plurality of polymer samples provideanother aspect for improving the sample throughput for a liquidchromatography system 10 or a flow-injection analysis system 20. Thepreferred rapid-serial withdrawal-preparation-delivery protocol can alsooptionally include, and will typically preferably include expelling aresidual portion of the pretreated sample from the auto-sampler probe,and cleaning the auto-sampler probe after delivering at least a portionof the pretreated sample. The expelling and cleaning can be effected asdiscussed above.

[0127] The particular sample-preparation (pretreatment) steps are notcritical, and desired pretreatment protocols are well known in the art.As discussed above in connection with the polymer sample, thepretreating step can comprise diluting the sample, separating one ormore components of the sample from other components thereof, and/ormixing the sample. These steps can be, and are preferably, effected withan auto-sampler, for example, as specified in the following exemplaryprotocols. Variations and other approaches for automated samplepreparation will be apparent to a person of skill in the art, and assuch, the present invention is not limited by these exemplary protocols.A polymer sample may be diluted with the auto-sampler to a concentrationrange suitable for detection by combining the expelled sample with adiluting agent (e.g., solvent) in the sample-preparation container.Preliminary, non-chromatographic separation of one or more non-polymercomponents (e.g., impurities) from a polymer sample may be effected withan auto-sampler as follows. The expelled polymer sample can be combinedwith a polymer-component-precipitating (“poor”) solvent, in thesample-preparation container, whereby polymer components and/or alsoother components are precipitated, but impurities remain in the liquidphase (poor solvent) within the preparation container. Theimpurity-containing liquid phase is then removed from thesample-preparation container—for example, by withdrawing the liquidphase into the auto-sampler probe and then discharging the liquid phaseinto a waste container. Washing steps may then be effected. Afterwashing the probe, if applicable, and optionally filtering or decanting,the auto-sampler probe can be used to deliver apolymer-component-dissolving (“good”) solvent to the preparationcontainer, whereby the polymer component and monomer components areredissolved to form a prepared polymer solution. Mixing of a polymersample (e.g., with an additional component) can likewise be convenientlyeffected with the auto-sampler in a rapid manner. In one approach,mixing can be effected by inserting the auto-sampler probe into theliquid in the sample-preparation container, removing the auto-samplerprobe from the sample-preparation container, and repeating the steps ofinserting and removing the auto-sampler probe at least once, andpreferably until adequate mixing is achieved. In another auto-samplermixing approach, the polymer sample can be mixed by withdrawing at leasta substantial portion of a liquid phase from the sample-preparationcontainer into the auto-sampler probe, expelling the withdrawnliquid-phase back into the sample-preparation container, and repeatingthe steps of withdrawing and expelling from and to thesample-preparation container at least once, and preferably untiladequate mixing is achieved.

[0128] Filters/Pulse-dampers

[0129] As noted above, aspects of sample preparation can also beeffected “in-line” within the flow characterization system. Referringagain to FIGS. 2A and 2B, for example, non-chromatographic separationcan, optionally, be effected with one or more in-line filters 104. Thein-line filter 104 can be of any suitable dimensions and mesh size. Inone embodiment, a filter 104 can retain particles having a diameter ofmore than about 0.5 μm. In another embodiment, a filter 104 can retainparticles having a diameter of more than about 0.2 μn. Other sizes mayalso be employed, as suitable for a particular polymer sample and/orprocess application. Additional in-line filters can likewise beemployed. While shown in FIGS. 2A and 2B immediately downstream of theinjection valve 100, the particular location of the filter is notcritical. Moreover, the polymer sample could be filtered as apreparation step, prior to loading of the polymer sample into the flowcharacterization system. Other in-line systems, such as pulse-damperscan also be employed.

[0130] Chromatographic Separation—Chromatographic Column

[0131] After injection of a polymer sample into a stream of liquidserving as a mobile phase of a liquid chromatography system, the polymersample is introduced into a chromatographic column containing aseparation medium having a stationary-phase for separation of one ormore components of the polymer sample from other components thereof.Separation is effected by selectively eluting one or more of the polymercomponents from the stationary-phase with a mobile-phase eluant. Thedegree of separation, also referred to as the resolution of the polymersample components, can vary depending on the particular chemical natureof the polymer sample components, and the quality of informationrequired in the particular characterization application. In general, theseparation performance in a given case can be controlled as a functionof the column design/geometry, the stationary-phase media, and theelution conditions with the mobile phase.

[0132] The particular design of a chromatographic column for liquidchromatography is, in the general case, not narrowly critical. A numberof columns known in the art can be employed in connection with thepresent invention—as purchased or with minor variations disclosedherein. In general, with reference to FIG. 2A, the chromatographiccolumn 102 of a liquid chromatography system 10 comprises an interiorsurface defining a pressurizable separation cavity having a definedvolume, an inlet port for receiving a mobile phase and for supplying apolymer sample to the separation cavity, and an effluent port fordischarging the mobile phase and the polymer sample or separatedcomponents thereof from the separation cavity. The separation cavity ispreferably pressurizable to pressures typically involved withhigh-pressure liquid chromatography—such pressures generally rangingfrom about atmospheric pressure to about 6000 psig (about 40 MPa). Insome preferred liquid-chromatography characterization methods, discussedin greater detail below, the chromatographic column can be relativelyshorter, and relatively wider, compared to traditional chromatographicseparation columns.

[0133] The chromatographic column 102 further comprises a separationmedium having a stationary-phase within the separation cavity. Theseparation medium can consist essentially of a stationary-phase or canalso include, in addition thereto, an inert support for the stationaryphase. The column 102 can also comprise one or more fillers, frits (forseparation medium retention and/or for filtering), and various fittingsand features appropriate for preparing and/or maintaining the column forits intended application. The particular separation medium to beemployed as the stationary-phase is not critical, and will typicallydepend on the separation strategy for the particular chemistry of thepolymer samples of interest, as well as on the desired detection,sample-throughput and/or information quality. Typical stationary-phasemedia can be a bed of packed beads, rods or other shaped-particles, or amonolithic medium (typically greater than about 5 mm in thickness), eachof which can be characterized and optimized for a particular separationstrategy with respect to the material, size, shape, pore size, pore sizedistribution, surface area, solvent regain, bed homogeneity (for packedshaped-particles), inertness, polarity, hydrophobicity, chemicalstability, mechanical stability and solvent permeability, among otherfactors. Generally preferred stationary-phase include porous media(e.g., porous beads, porous monoliths), such as are suitable for gelpermeation chromatography (GPC), and media suitable forprecipitation-redissolution chromatography, adsorption chromatography,and/or reverse-phase chromatography. Non-porous particles or emptycolumns and/or capillaries with adsorptive walls can be used as well. Ifbeads are employed, spherical beads are preferred over other shapes.Particularly preferred stationary-phase media for polymercharacterization applications are disclosed in greater detail below, butcan generally include silica, cross-linked resins, hydroxylatedpolyglycidyl methacrylates,(e.g.,poly(2-3-dihydroxypropylmethacrylate)), poly(hydroxyethyl methacrylate),and polystyrenic polymers such as poly(styrenedivinylbenzene).

[0134] The mobile-phase fluid(s) employed to elute one or more polymercomponents from a chromatographic stationary-phase are not generallycritical, and can vary depending on the chemistry of the separationbeing effected. The mobile phase can be varied with respect tocomposition, temperature, gradient rates, flow-rates, and other factorsaffecting selectivity, speed of separation, peak capacity (e.g., maximumnumber of components that can be separated with a single run) and/orresolution of a polymer component. Exemplary mobile-phase fluids for GPCinclude tetrahydrofuran (THF), toluene, dimethylformamide, water,aqueous buffers, trichlorobenzene and dichlorobenzene. Exemplarymobile-phase fluids for precipitation-redissolution chromatographyinclude THF, methanol, hexane, acetone, acetonitrile and water. Foradsorption chromatography, the mobile phase can include, for example,hexane, isooctane, decane, THF, dichloromethane, chloroform,diethylether and acetone. For reverse-phase chromatography, the mobilephase can include water, acetonitrile, methanol and THF, among others.

[0135] Significantly, preferred mobile phase flow rates—for liquidchromatography and/or for flow-injection analysis systems—are typicallyfaster than flowrates employed conventionally for high-pressure liquidchromatography. The flowrates can vary, depending on the separationbeing effected, but can, in many instances, range from about 0.1 ml/minabout 25 ml/min, and preferably range from about 1 ml/min to about 25ml/min. It may be desirable, for some detector configurations, to splitoff a part of the sample-containing mobile phase such that the flow rateto a particular detector is reduced to an acceptable level. For liquidchromatography systems, such a split would typically occur after thecolumn and before the detector.

[0136] Microprocessors

[0137] Referring to FIG. 2A, FIG. 2B and FIG. 4, one or moremicroprocessors can, as noted above, be employed for controlling everyaspect of the flow characterization systems, including: the pump 116(e.g., mobile-phase flow-rate, flow-rate gradients, compositionalgradients, temperature gradients, acceleration rates for suchgradients); the reservoir 114 (e.g., temperature, level); theauto-sampler 200 (e.g., movements between spatial position, timingthereof, sample selection, sample preparation, sampling pump flow-rates,and other operations), the injection valve 100 (e.g., timing, selectionof sample loops, etc.); the column 102 (e.g., column selection (ifmultiple columns and automated column-switching valves are present),column temperature); the detector 130 (e.g., data acquisition (e.g.,sampling rate), data processing (e.g., correlation); the detectorparameters (e.g., wavelength); and/or overall system conditions (e.g.,system pressure, temperature). Software is typically available fromdetector and/or liquid chromatography system manufacturers (e.g.,MILLENIUM™ 2000 software available from Waters (Milford, Mass.).

[0138] Preferred Liquid Chromatography Protocols

[0139] An individual polymer sample is preferably characterized with aliquid chromatography system by withdrawing a polymer sample from asample container into a probe of an auto-sampler at a first withdrawaltime, t_(ASW1). At least a portion of the withdrawn sample is thenexpelled from the auto-sampler probe into a liquid chromatography systemand the loaded sample is injected into the mobile phase thereof. Atleast one sample component of the injected sample is separated fromother sample components thereof in a chromatographic column. At a seconddetection time, t_(LCD1), a property of at least one of the separatedsample components is detected. The characterization protocol can alsoinclude pretreating the withdrawn sample prior to injection, suchpretreating comprising sample preparation steps as described. The stepsof withdrawing the polymer sample, injecting at least a portion thereofinto the mobile phase of the liquid chromatography system,chromatographically separating one or more components of the sample, anddetecting a property of the sample or of a component thereof arepreferably controlled such that the period of time required tocharacterize the polymer sample, the liquid-chromatographycharacterization period, delineated by the difference in time,t_(LCD1)−t_(ASW1), is not more than about 4 minutes. Theliquid-chromatography characterization time is preferably less thanabout 4 minutes, and depending on the quality of information required,can be less than about 2 minutes, less than about 1 minute, less thanabout 30 seconds, less than about 20 seconds or less than about 10seconds. The rapid liquid chromatography protocols of the invention havecommercial application with respect to a single, individual polymersample, for example, in field-based research such as processtroubleshooting. As noted, however, substantial commercial applicationsrelate to pluralities of polymer samples.

[0140] A plurality of polymer samples is preferably characterized with aliquid chromatography system as follows. A first polymer sample iswithdrawn from a first sample container, optionally pretreated inpreparation for characterization, and then at least a portion thereof isloaded into an injection valve of the liquid chromatography system. At afirst injection time, t_(LCI1), the loaded first sample is injected fromthe injection valve into a mobile phase of the liquid chromatographysystem. At least one sample component of the injected first sample ischromatographically separated from other components thereof in achromatographic column. A property, preferably an optical property, ofat least one of the separated sample components of the first sample isthen detected. One or more properties of interest (e.g., weight-averagemolecular weight, composition and/or conversion values) can bedetermined from the detected property of the first sample or componentthereof.

[0141] Meanwhile, a second polymer sample is withdrawn from a secondsample container. If the same withdrawal instrument is employed, theinstrument is preferably cleaned after loading the first sample into theinjection valve and before withdrawing the second sample. The secondsample is optionally pretreated in preparation for characterization, andat least a portion of the withdrawn second sample is then loaded intothe injection valve of the liquid chromatography system. At a secondinjection time, t_(LCI2), the loaded second sample is injected into themobile phase of the liquid chromatography system. At least one samplecomponent of the injected second sample is chromatographically separatedfrom other sample components thereof in the chromatographic column, andthen a property of at least one of the separated sample components ofthe second sample is detected. One or more properties of interest (e.g.,weight-average molecular weight, composition and/or conversion values)can be determined from the detected property of the second sample orcomponent thereof.

[0142] The steps of withdrawing the polymer sample from the samplecontainer, optionally preparing the sample, loading the sample into theinjection valve, injection of the sample into the mobile phase,chromatographic separation of the polymer sample and/or detection of aseparated sample component are controlled such that the liquidchromatography cycle time, TLC, delineated as the difference in betweensample injections into the mobile phase of the liquid chromatographysystem, t_(LCI2)−t_(LCI1), is not more than about 10 minutes. The cycletime is preferably not more than about 8 minutes, and can be, asdiscussed above depending on the desired quality resolution of thedetected property (or of properties of interest determined therefrom),less than about 4 minutes, less than about 2 minutes, less than about 1minute, less than about 30 seconds, less than about 20 seconds and lessthan about 10 seconds.

[0143] Controlling the efficiency of chromatographic separation is animportant aspect of achieving high sample-throughput with acceptableinformation quality. In general, the column geometry, stationary-phase(e.g., permeability, porosity, size, shape, distribution, surface area,surface chemistry), mobile-phase (e.g., eluant composition, eluanttemperature, eluant flow rate, gradient profiles for eluant composition,temperature and/or flowrate) are controlled such that thesample-throughput is not more than about 10 minutes per sample. Thesefactors are preferably controlled, individually, in combination witheach other, or in combination with other factors, to achieve anaverage-sample throughput within the times and ranges previouslyspecified. Generally, liquid chromatography relies upon separation basedon a particular polymer property (e.g. size) or on a particular polymercomposition (e.g., chemistry). Separations to be effected based on size(e.g. hydrodynamic volume) of a polymer sample component can preferablyemploy GPC media and protocols, somewhat less preferablyprecipitation-redissolution, and even less preferably reverse-phase(hydrophobic) media or adsorption or normal-phase (hydrophilic) media.Where the separation strategy is to effect a separation based on theparticular chemistry of the polymer sample components, the adsorption,normal-phase and reverse-phase chromatography approaches are preferablyemployed, while precipitation-redissolution approaches are somewhat lesspreferred and GPC approaches are even less preferred. More than one typeof column or separation method may be combined, such as GPC incombination with one of adsorption chromatography, reverse-phasechromatography or precipitation-redissolution chromatography. Suchapproaches allows simultaneous, rapid separation of polymeric componentsby size (e.g., R_(h)) and separation of non-polymeric smaller sizecomponents by chemistry (e.g., polarity). Because polymer separationoccurs, this embodiment allows for measurements of distributions ofproperties, such as distribution of chemical composition or adistribution of molecular weight for each sample.

[0144] The particular configuration of the liquid chromatography systemused in connection with the present case is not, in the general case,narrowly critical. An exemplary liquid chromatography system is depictedschematically in FIG. 6. Briefly, the liquid chromatography system 10comprises an injection valve 100, chromatographic column 102, andcontinuous-flow-through detectors 130, 132. A polymer sample 20 can beloaded into the injection valve 100 from one or more places, eitherdirectly via injection ports 108, 108′ or indirectly through a loadingport 204 and transfer line 206. First, a polymer sample 20 (or aplurality of polymer samples) may be loaded with a robotic auto-sampler104 that is external to a heated environment (e.g., oven 112) bywithdrawing a sample from, for example, a library of samples 106 stagedfor auto-sampling, and injecting the sample into the loading port 204. Asample can also be loaded into the injection valve 100 through a manualinjection port 108. As another alternative, a polymer sample can beloaded into the injection valve by an auto-sampler 110 that is inside(i.e., internal to) the heated environment (e.g., controlled temperatureoven 112). One or more mobile-phase fluids (e.g., solvents) can bestored in reservoirs 114, 120 having dedicated pumps 116, 118 thatprovide the pressure for pumping the mobile-phase fluids through thesystem 10—including column 102 and detectors 130, 132. The pumps 116,118 can be controlled by a computer 122. If a mobile-phase temperaturegradient is desired, (e.g., in applications discussed below), a coldermobile-phase fluid can be in one reservoir and a hotter mobile-phasefluid can be in another reservoir. For example, a hotter solvent cancome from reservoir 114 via pump 116 and the colder solvent can comefrom reservoir 120 via pump 118. In such cases, valves 124, 126 can beappropriately manipulated—manually or automatically—to open and/orclose, preferably allowing for injection of the colder solvent justprior to the column 102. Check valves 123 can also be used for flowcontrol. The solvent can, in this embodiment, remain cold because itwill not enter the oven 112 until just prior to injection. Afterchromatographic separation in column 102, the polymer sample orcomponents thereof may be detected by one or more detectors 130, 132.The detectors can be both internal to the heated environment, as shownin FIG. 6, or alternatively, one or more or all of the detectors canreside externally to the heated environment. The detectors arepreferably connected to a computer 134 to collect and process the dataobtained from the detectors. In an exemplary configuration, detector 130can be a light scattering detector and detector 132 can be a refractiveindex detector or an evaporative mass detector. Following detection, thepolymer sample can be exhausted to a waste container 140.

[0145] The following protocols can be effectively applied individually,or in combination, and moreover, can find applications with low-,ambient-, or high-temperature characterization protocols.

[0146] Column Geometry

[0147] In some preferred liquid-chromatography characterization methods,the chromatographic column can be relatively shorter, and relativelywider, compared to traditional chromatographic separation columns. Thetypical geometry of a conventional column is long and narrow, rangingfrom about 4-8 mm in diameter and from about 30-50 cm in length,respectively. Typically, three or four columns are employed in seriesfor each separation.

[0148] Unlike conventional approaches, preferred liquid chromatographicmethods of the present invention can employ columns that are relativelyshort and wide. More specifically, the chromatographic column can havean aspect ratio ranging from about 0.1 to about 1, where the aspectratio is defined as the ratio of column-separation-cavity width to thecolumn-separation-cavity height dimensions (e.g., diameter/height—basedon a right-cylindrical-shaped separation cavity). In preferredembodiments, the chromatographic column can, for some applications, havean aspect ratio ranging from about 0.3 to about 1, and can also rangefrom about 0.5 to about 1. The actual dimensions for such columns arenot critical, but the separation cavity of a column can typically have ahydraulic radius ranging from about 0.1 cm to about 1 cm. Forright-handed cylindrical separation cavities, the diameter can rangefrom about 0.5 cm to about 3 cm, and the length can range from about 1cm to about 7 cm. Preferably, the columns can have diameters rangingfrom about 0.75 cm to about 2 cm and a length ranging from about 3 cm toabout 5 cm.

[0149] Reducing the column length while increasing the column widthdecreases the separation time required for a particular polymer sample.Without being bound by theory, employing relatively shorter columnsresults in shorter retention times at the same flow rate. Moreover, areduction in length and an increase in the column diameter results inreduced back-pressure, thereby allowing the use of higher mobile-phaseflowrates before affecting the structural integrity of the solid-phasemedia. A limitation to this approach for optimizing the column, however,is the desired resolution of the detected property versus time—which canbe given by the number of theoretical plates per the column. Decreasedcolumn efficiency in high-speed separations may result in peakbroadening—thereby providing less detailed information on distributionof molecular weight (e.g., calculated using GPC calibration). However,the values of the peak-average molecular weights (M_(peak)) arerelatively unaffected. Reliable values of polydispersity can be thenobtained either by mathematical adjustment of data based on thechromatographic broadening of narrow molecular weight standards, ordirectly by using light-scattering detection. Despite such limitations,the achievable degree of separation of polymer components is,nonetheless, satisfactory for many polymer characterizationapplications—particularly for screening of combinatorial libraries ofpolymer components. Hence, such a relatively short and high-aspect ratiochromatographic column provides a further aspect for improving thesample throughput for a liquid chromatography system 10 or aflow-injection analysis system 20.

[0150] Chromatographic columns having the above-recited aspect ratiosare preferably combined with porous stationary-phase media suitable forgel-permeation chromatography. In one preferred method forcharacterizing a plurality of polymer samples, the samples are seriallyinjected into a mobile phase of a liquid chromatography system. At leastone sample component of the injected samples are separated from othersample components thereof in a chromatographic column having a porousmedia stationary-phase and an aspect ratio ranging from about 0.1 toabout 1. A property of at least one of the separated components of theplurality of samples is detected. When a plurality of samples are to becharacterized with such a column, the sample-throughput is preferably asrecited above.

[0151] Selection of a particular porous media to effect the separationcan be guided by the particular sample components being separated. Ingeneral, the porous media stationary-phase employed in connection withsuch method can have a relatively wide range of porosities, such as areobtained with typical “mixed bed” GPC stationary-phase media, andtypically expressed by a molecular weight exclusion limit ranging fromabout 20,000 to well over 10,000,000. Preferred “mixed-bed”stationary-phase media are PLGel Mixed-B and PLGel Mixed-C (PolymerLaboratories).

[0152] As an alternative to a single column having a stationary-phaseporous media with a range of porosities, two or more of the relativelyhigh-aspect ratio columns can be employed with each column having a morenarrow range of porosities. In one such embodiment, for example, twohigh-aspect ratio columns are arranged in series in theliquid-chromatography mobile-phase flow path. One of the columns canhave a porous media with pore sizes of about 10³ Å—such pore size beingeffective for capturing relatively small molecules having a relativemolecular weight of up to about 20,000, while allowing molecules largerthan about 20,000 to pass through quickly. The other of the columns canhave a porous media with pore sizes of about 10⁵ Å—such pore size beingeffective for capturing and chromatographically separating moleculeshaving a relative molecular weight ranging from about 50,000 to about2×10⁶. As another example of such rapid size exclusion chromatography,one of the columns can have a porous media with pore sizes of about 10³Å with a second column having a porous media with pore sizes of about 30Å. (See Ex. 15). Such porous media can be obtained commercially fromPolymer Laboratories or Polymer Standard Service, among many others.

[0153] In other embodiments, however, the relatively high-aspect ratiocolumns can be advantageously employed singly with porousstationary-phase media having narrower, more focused porosity ranges.For example, the porous media can be selected to have a porosityselected to effectively separate molecules having molecular weightsranging from about 10⁴ D to about 10⁶ D. Such porous media can beobtained commercially from Polymer Laboratories or Polymer StandardService, among others. Other narrowly tailored porosity ranges can alsobe employed with the relatively short, relatively wide column asdiscussed below in connection with targeted separation.

[0154] In other variations, the short column may comprise columnstationary-phase packing other than is typically used for GPC, such asnormal-phase or reverse-phase silica particles, polymer monoliths,inorganic monoliths, and other well-known column stationary-phasematerials or filter media. For example, short columns containingadsorption chromatography stationary-phase can be used to removecomponents either more polar or less polar than the polymer sample ofinterest, such as water or solvents initially introduced with thesample. Also in a preferred aspect of this embodiment, more than oneshort column may be used in series, for example a short GPC column incombination with a short normal-phase adsorption chromatography column,such that polymer is separated from low-molecular-weight components,which are then further separated by polarity. (See Ex. 20). This can beparticularly useful for rapidly separating polymer from residual monomeror solvent in a polymerization reaction, and then further quantifyingthe type and amount of monomer or solvent within a single, rapidanalysis.

[0155] The detector employed in connection with a polymercharacterization method using the relatively high-aspect ratio column isnot critical, and can generally include one or more of those detectorspreviously described. Preferably, a weight-average molecular weight canbe determined from one or more detected properties. In preferredconfigurations, however, the high-aspect ratio geometry columns arecombined with the detector configurations described below in connectionwith rapid-fire light-scattering techniques.

[0156] When the liquid chromatography approach involves size exclusionchromatography, such approaches can be referred to as “rapid SEC”approaches. When the size-exclusion separation is effected as gelpermeation chromatography, the approaches can be referred to as “rapidGPC” approaches. Generally, optimized column designs for particularpolymer sizes of interest can increase the speed of separations ofpolymer samples (e.g., elution time) substantially compared to typicalGPC elution times, which typically require about 40 minutes to an hour.By combining the optimized column designs with the GPC beads, preferablyof a specific pore size as discussed below, elution times for polymersample separation can be reduced, in comparison to typical GPCseparations, on the order of 10 times, preferably 20 times and mostpreferably 40 times. Thus, if typical GPC elution times are in the rangeof 40 minutes, the elution times of the GPC separations of thisinvention are less than about 4 minutes, preferably less than about 2minutes and most preferably less than about 1 minute.

[0157] Targeted Separation

[0158] In many combinatorial research applications, a target polymerproperty (e.g., molecular-weight) is predefined. As such, thescreening/characterization method can be targeted for sensitivity to thepredefined target polymer property. For example, a screen may bedesigned to determine whether a polymer sample comprises a polymercomponent within a particular predetermined molecular weight range orparticle size range. In such cases, it may not be necessary to measure aprecise value for a sample if it outside of the predetermined range.

[0159] Such targeted separation protocols can be effectively employedwith size exclusion chromatography such as gel permeation chromatography(GPC). Use of targeted-separation GPC techniques—with porosity of thestationary-phase media (e.g. beads) in the column being changed orvaried in comparison to standard GPC beads as described herein—ispreferably combined with an altered, optimized geometry of the GPCcolumn, again in comparison to standard GPC columns—such as therelatively-high aspect ratio column designs discussed above.

[0160] While some aspects of the following description refer to “beads”,such reference is to be considered exemplary; other stationary-phasemedia (e.g., rods, monoliths, etc.) can be readily employed instead ofsuch beads.

[0161] With respect to bead porosity, standard GPC columns use beadshaving nominal pore sizes from several nm up to several hundreds of nm,capable of differentiating between dissolved polymer chains witheffective hydrodynamic radii (R_(h)) ranging from about 2 nm up to about100 nm. Both the pore size of the beads and the effective R_(h) of thepolymer chains is dependent on the chromatographic solvent used, as wellas other factors such as temperature and/or ionic strength. In mostcommon cases, columns with mixed porosity beads are used to achievelinear GPC calibrations, requiring a random distribution of differingpore sizes over a broad range of sizes. However, in such a case theresolving ability of the column for polymers with very close molecularweights is limited.

[0162] Therefore, one embodiment of this invention uses beads havingporosity selected for rapid separation of polymer chains with a smallerrange of R_(h), corresponding to a particular molecular weight range,such as the molecular weight range targeted by the synthesis conditionsused to prepare a combinatorial library. For polymers having molecularweights in the range of 10⁴ to 10⁵ beads having porosity from 50 to 100nm are typically employed. For polymers having molecular weights in therange of 10³ to 10⁴ beads having porosity of 10-30 nm are usuallyemployed. Conversely, for polymers having molecular weights in the rangeof 10⁵ to 10⁶ beads having a porosity of several hundreds of nanometersare employed. The precise pore sizes suitable for separation ofmacromolecules in certain range of the molecular weights depends also onthe structure and solvent interactions of both stationary-phase packingmaterials and polymer characterized.

[0163] Examples of useful porous beads of this invention include: Pl Gelfrom Polymer Laboratories of various pore sizes; Suprema Gel 30 Å and1000 Å from Polymer Standard Services (of 3 and 100 nm nominal poresize); and GM-Gel 3000 and 5000 from Kurita (of 380 and 540 nm nominalpore size ). The composition of the beads is cross-linked polystyrene,poly(2,3-dihydroxypropyl methacrylate), and rigid polysacchariderespectively.

[0164] Use of the beads of appropriate porosity for separating polymersor particles in particular size ranges allows the use of columns severaltimes shorter than for similar separation obtained using a typical setof conventional GPC columns (such as series of three 30 cm columns).Hence, the combination of targeted-separation stationary-phase mediawith optimized column geometry is a particularly-preferred embodiment ofthe invention.

[0165] One example of separation using the optimized column geometry andtargeted-separation techniques together involves the screening and/orcharacterization of emulsion polymer particles. Emulsion polymer samplescomprising polymer particles having a hydrodynamic radii up to about 200nm can be separated on a column packed with a macroporous rigid beadsvia size-exclusion. A property of the polymer samples can be detectedwith a mass detector (e.g., RI or ELSD/EMD). For such a separation, thecolumn preferably has a length of about 3.0 cm and a width of about 1.0cm, the stationary-phase porous media packing material has an effectivepore size of about 340 nm or 540 nm, and the flow-rate of the mobilephase can range from about 2 ml/min to about 10 ml/min. Effectiveparticle size separation and characterization, with reasonably goodquality, is obtained at a rate of about 50 seconds per sample.

[0166] Rapid-fire Light Scattering

[0167] Methods involving short, high-aspect ratios columns, withtargeted separation medium and one or more light-scattering detectorsare referred to herein as “rapid-fire light-scattering” (RFLS) methods.

[0168] In one preferred RFLS method for characterizing a plurality ofpolymer samples, a polymer sample is injected into a mobile phase of aliquid chromatography system, and a low molecular-weight fraction of theinjected sample—comprising sample components having molecular weights ofnot more than about 1000—is separated from a high-molecular weightfraction thereof in a chromatographic column. The high molecular-weightfraction—comprising sample components having molecular weights of morethan about 1000 (including substantially all of the polymer component)is allowed to pass through the chromatographic column withoutsubstantial separation thereof. A property of the high molecular-weightfraction or of a component thereof is then detected. These steps arethen repeated for each of the plurality of polymer samples, in arapid-serial manner.

[0169] In this preferred method, the column preferably comprises aporous stationary-phase media having a range of pore sizes thatfacilitate passage of the high-molecular weight fraction and separationof the low molecular-weight fraction from the high molecular-weightfraction. Moreover, the column preferably has a geometry such as that ofthe relatively high-aspect ratio columns described above. Specifically,the high-aspect ratio columns are preferably cylindrical with a lengthof about 1-5 cm and a width (diameter) of about 4 mm to about 1 cm. Thecolumn volume ranges from about 0.2 mL to about 4 mL. The flow rate, inthis preferred method, is typically faster than for normalchromatographic separation. Preferred mobile-phase flow rates are on theorder of 1-40 mL/min, and more preferably from about 1 ml/min to about25 ml/min. Faster flow rates, combined with relatively small volume ofthe system, results in a shorter residence time of the polymer sample inthe flow system, and therefore, a higher speed of characterization.Polymer properties can be determined for a plurality of samples at anaverage sample-throughput ranging from about 4 seconds to about 40seconds per sample. When a polymer sample is measured by this methodusing a differential refractive index detector and a static lightscattering detector, M, values for multiple polymer samples can bedetermined at a rate that, compared to a minimum of about 20-40 minutesper sample using typical conventional GPC/light scattering techniques,represents an improvement in throughput of 30-600 times.

[0170] This preferred approach can effectively separate polymercomponents from non-polymeric components of the polymer sample. Hence,the low-molecular weight fraction can include many non-polymericcomponents, such as dust particles and small molecules, such as solvent,residual catalyst and/or residual monomer. Such separation can improvethe accuracy of polymer property determinations, depending on the sourceand purity of the polymer to be analyzed. In this aspect, this approachis particularly useful for screening a library of polymerization productmixtures from a combinatorial synthesis—where the polymer sample maycomprise both polymeric and low-molecular weight components.

[0171] The detector configuration employed in connection with RFLStechniques is not critical. Preferred configurations include, briefly:(1) a mass detector (e.g., RI detector, ELSD) combined with a SLSdetector to determine the weight-average molecular weight, M_(w), of thepolymer sample—preferably of a polymer solution; (2) a mass detector(e.g., a RI detector, ELSD) combined with a SLS detector to determineparticle of a polymer sample—preferably of a polymer dispersion oremulsion; (3) a DLS detector (by itself) to determine the averageparticle size or a size distribution of a polymer sample—preferably of apolymer dispersion or emulsion, or alternatively, to determine anaverage molecular weight or a molecular weight distribution of a polymersample—preferably of a polymer solution; (4) a SLS detector (by itself)at two or more angles (typically, but not necessarily 90° and 15° C.) todetermine a weight-average molecular weight; and/or (5) SLS and DLStogether to determine the radius of gyration and the hydrodynamicradius, which can be used to provide an indication of branching andhigher-order conformation and/or architecture. The high-aspect ratiocolumn can also be employed with other detector configurations,including for example: (1) an RI detector (by itself) with samples ofknown concentration to determine dn/dC—useful as an indicator forchemical composition; (2) a UV-VIS or photodiode array detector combinedwith a light scattering and mass detectors—for compositiondeterminations; and/or (3) a viscometric detector in combination withother detectors to provide additional useful information about thesample, such as polymer branching.

[0172] Precipitation-redissolution Chromatography

[0173] Precipitation-redissolution chromatography involves the use ofmobile phase having a solvent gradient in conjunction with an insolublestationary-phase (e.g., a polymer monolith). The polymer sample isinjected into a mobile-phase solvent that is a “poor” solvent for thepolymer being characterized (sometimes called a “non-solvent”), therebycausing precipitation of the polymer sample. The precipitated polymersample then adsorbs onto the stationary-phase (e.g., monolith) surface.Gradually, a better solvent for the polymer being characterized isintroduced into the mobile phase. When the better solvent contacts theprecipitated polymer sample, the smaller particles of the polymer sampleredissolve first. As more of the better solvent contacts theprecipitated polymer sample, larger particles of the polymer sampleredissolve, until the entire polymer sample has been redissolved. Inthis fashion, the polymer sample is separated by size (with the smallerparticles corresponding to smaller size molecules). Solvent choicesdepend on the solubility characteristics of the polymer samples beingcharacterized. For a typical hydrophobic polymer such as polystyrene,“good” solvents include tetrahydrofuran, toluene, dichloromethane, etc.,while “poor” non-solvents include methanol, ethanol, water, or hexane.It is generally preferred that the good solvent and the poor solventused for any particular separation be miscible.

[0174] The speed of separation of the precipitation-redissolutionchromatographic techniques depends on the gradient profiles (e.g., thetime rate of change of the mobile-phase composition—between solvent andnon-solvent). Typical pump systems supplied by HPLC equipmentmanufacturers have sufficient speed and accuracy such that the rate ofintroduction of the better solvent can be controlled to effectivelyelute the precipitated polymer sample in about 1 minute or less, and insome cases, less than about 45 seconds. Flow rates of the mobile phaseare preferably about 5 mL per minute and higher, up to the limit of thepump system used, which can be 20-40 mL per minute for commercial pumpswith large-volume pump heads.

[0175] Since polymer solubility is also a function of temperature,temperature gradients can also be employed, individually or incombination with the mobile-phase compositional (e.g., solvent)gradient. While this technique is discussed in greater detail below inconnection with high-temperature liquid chromatography, thetemperature-gradient technique can also have applications at relativelylow temperatures—near ambient or below, depending on the particularpolymer samples being characterized. Briefly, the sample is introducedat a lower temperature, enhancing precipitation of the polymer, and thenthe temperature is increased (optionally in conjunction with a change incomposition of the mobile phase to a good solvent) to allow selectivedissolution and elution of retained polymer.

[0176] The precipitation-redissolution chromatography approachesdescribed herein—particularly employing monolithic columns such as thosedisclosed by Petro et al., vide supra., generally lead to high-speedcharacterization with good quality of information.

[0177] Adsorption Chromatography

[0178] Adsorption chromatography using solvents selected for particularpolymers or polymer libraries is an alternative method of this inventionfor rapidly separating polymer samples. In this technique, the polymersample is reversibly adsorbed from the mobile phase onto thestationary-phase of the column. Adsorption can be enhanced by solventselection such that the polymer samples have decreased solvency in thechosen “weaker” solvent, as compared to a “stronger” solvent thatcompletely dissolves the polymer samples. As such, the adsorption and/orsubsequent desorption can be faster.

[0179] The solid-phase media can be selected according to the type ofpolymer to be analyzed. Exemplary solid-phase media for this approachinclude porous monoliths and beads. Silica or hydrophilic polymer beadsare used for adsorption of polar polymers or for removing of highlypolar components of the samples, such as water, which would otherwiseinterfere with the analysis of compounds of interest, such as monomersand polymers. Polymeric beads with diol functionalities are preferredfor this purpose since they have higher adsorptivity than silica withminimized non-specific interactions with the characterized polymers (SeeM. Petro, et al., Anal. Chem., 1997, 69 3131; M. Petro, et al., J.Polym. Sci. A: Polym. Chem., 1997, 35, 1173; J. M. J. Frechet, et. al.,Polym. Mater. Sci. Eng. 1997, 77, 38.).

[0180] The typical mobile phase (e.g., solvent) used for this adsorptionchromatography is tetrahydrofuran, either alone or in mixtures withhexane (to enhance adsorption) or water (to enhance elution).Octadecyl-silica beads (commonly used in conventional reverse-phaseHPLC) and polystyrene-based monoliths are used for a separation ofcompounds of medium polarity under the conditions typical ofreversed-phase chromatography, usually in combination with a mixture ofwater and tetrahydrofuran. Optionally, gradients in connection with thistechnique can be employed, changing either the composition, temperatureor flow rate of the mobile phase.

[0181] Overlaid Injection/Low-MW Insensitive Detection

[0182] Another preferred approach for characterizing a plurality ofpolymer samples takes advantage of the fact that chromatographicseparation is typically a rate-limiting step for liquid chromatographycharacterization systems. According to this approach, the effectiveseparation time is reduced by serially overlapping samples. Since agiven sample is being processed closer in time to the preceding and thesuccessive sample, the overall sample-throughput is improved.

[0183] More specifically, a plurality of polymer samples can becharacterized by injecting a first polymer sample into a mobile phase ofa liquid chromatography system, separating at least one sample componentof the injected first sample from other sample components thereof in achromatographic column, and detecting at least one property of theseparated sample component of the first sample. The second polymersample is then injected into the mobile phase of the liquidchromatography system at a particuarly-controlled time, referred to forpurposes herein as the successive-sample injection time, t_(LCI2). Atleast one sample component of the injected second sample is separatedfrom other sample components thereof, and at least one property of theseparated sample component of the second sample is detected. The cycleis repeated for each pair of preceding/successive polymer samples in theplurality of polymer samples. In preferred applications, at least 8different polymer samples are characterized according to the method.

[0184] The successive-sample injection time, t_(LCI2), is an importantfactor in connection with this approach. In general, the particulardegree of overlap between successive samples can vary, depending on thedesired throughput and information quality. Preferably, the secondpolymer sample is injected into the mobile phase of the liquidchromatography system at an injection time that provides an averagesample-throughput of not more than about 10 minutes per sample for theplurality of samples.

[0185] In one approach, the second polymer sample can be injected whiledetecting at least one property of the separated sample component of thefirst sample. In another approach, effectively providing a somewhatgreater degree of overlap, the second polymer sample can be injectedwhile separating at least one sample component of the injected firstsample from other sample components thereof. In a further approach,providing even a greater degree of overlap, the second polymer samplecan be injected while advancing the injected first sample to thechromatographic column.

[0186] Viewed from another aspect, the second polymer sample can beinjected such that the trailing edge of a detection profile for thefirst sample overlaps with the leading edge of a detection profile forthe second sample. That is, the serial injection of polymer samples intothe mobile phase can be at a rate that compresses the allowed cycle timeso much that the sample components from a first sample and samplecomponents from a successive second sample reside in the detectioncavity of the detector simultaneously. In GPC applications, for example,in which stationary-phase is a porous media, the later-elutingsmaller-molecule components of the first sample can be present in thedetection cavity of the detector at the same time as theearlier-eluting, larger-molecule components of the second sample. Ananalogous effect can be realized with other chromatographic separationapproaches, such as precipitation-redissolution chromatography oradsorption chromatography or reverse-phase chromatography.

[0187] In flow-injection analysis approaches, the overlaid samples canbe compressed even further. For example, the compression can be suchthat the samples have overlapped leading and trailing portions orregions, with only a small volume (e.g., sufficient for detectionpurposes) of pure, non-overlapped sample, available for detection in adetection cavity.

[0188] In such overlapped cases, and in particular those cases in whichcomponents from a preceding and a successive polymer sample reside inthe same detection cavity at the same time, it is advantageous to employa detector that is insensitive to the sample components from one of thesamples. For example, in the exemplary case based on GPC, it isadvantageous to employ a detector that is insensitive to samplecomponents having low molecular weights—corresponding to thelater-eluting sample components of the first (preceding) polymer sample.Preferably, a detector is employed that is insensitive to samplecomponents having a weight-average molecular weight of less than about1000. The detector can, most preferably, be an evaporativelight-scattering detector (ELSD).

[0189] The overlaid-injection approach described herein allows forsubstantial improvements in sample throughput. For example, completemolecular weight information (including PDI) and composition for aplurality of samples can be obtained—with a level of quality comparableto conventional GPC—using an “accelerated size exclusion chromatography”approach that incorporates this technique. (See Ex. 17 and Ex. 18). Thisapproach is suitable for determining a characterizing property ofinterest, evaluating monomodality versus polymodality, and evaluatingpurity with a sample throughput of not more than about 8 minutes persample. In another application of the overlaid-injection approach,average molecular weights and molecular weight distribution informationcan be obtained—with a level of quality that is reasonably good using a“rapid size exclusion chromatography with enhanced resolution” approach.(See Ex. 16).

[0190] Preferred Flow-injection Analysis Protocols

[0191] A plurality of polymer samples are characterized according to thepresent invention with a flow-injection analysis system by seriallyinjecting a plurality of polymer samples into a mobile phase of acontinuous-flow detector, and detecting a property of the injectedsamples or of components thereof with the continuous-flowdetector—preferably at an average sample-throughput of not more thanabout 10 minutes per sample. In some embodiments, two or morecontinuous-flow detectors are used in series. The combination of two ormore detectors allows for the determination of certain polymerattributes of interest. Because no substantial chromatographicseparation of the polymeric components of the sample occurs,flow-injection analysis allows for measurement of properties of aheterogeneous polymer sample, such as average properties (e.g., averagecomposition or average molecular weight) or, with some detectors (e.g.,dynamic light-scattering detectors) specific component properties. Thisembodiment may be particularly rapid, limited only by the speed of thesampling or by the residence time of the liquid in the flow system. Thisembodiment is particularly useful for rapid screening of combinatorialpolymerization reactions, especially to determine polymerizationconditions or characteristics.

[0192] In a preferred approach, a plurality of polymer samples arecharacterized with a flow-injection analysis system as follows. A firstpolymer sample is withdrawn from a first sample container, preferablyinto a probe of an auto-sampler. At a first injection time, T_(FII1), atleast a portion of the withdrawn first sample is injected into themobile phase of the continuous-flow detector, and advanced toward adetection-cavity of a detector—without substantial chromatographicseparation thereof. A property of the injected first sample or of acomponent thereof is detected while the sample resides in the detectioncavity of the detector. A second polymer sample is withdrawn from asecond sample container. At a second injection time, t_(FII2), at leasta portion of the withdrawn second sample is injected into the mobilephase of the continuous-flow detector. A property of the injected secondsample is detected.

[0193] In general, the steps of withdrawing the polymer samples,injecting at least a portion of the withdrawn polymer samples into themobile phase of a flow-through detector, advancing the injected samplestoward the detection cavity of the detector, and detecting a property ofthe injected samples are controlled such that the flow-injection cycletime, T_(FI), delineated by the difference in time, t_(FII2)−t_(FIII1),is not more than about 10 minutes. Hence, the speed of detection islimited, in a practical sense, by sampling rates, mobile phase flow ratein the flow-injection analysis system, and required sample residencetime in the continuous-flow detector. In preferred embodiments, theflow-injection cycle time is not more than about 8 minutes, andpreferably less than 4 minutes, less than 2 minutes, less than 1 minuteor less than 30 seconds. Flow-injection cycle times of less than 20seconds, and less than 10 seconds can also be achieved.

[0194]FIGS. 7A and 7B show a preferred configuration for aflow-injection analysis system 20. An auto-sampler 200 (described inconnection with FIG. 4) withdraws a sample 20 from a sample container202 into an injection probe 201. A mobile phase is supplied to thesystem 20 from reservoir 114 via pump 116. The polymer sample 20 isinjected into the mobile phase—either directly (not shown) or indirectlyvia loading port 204, and is advanced through sample transfer line 206to valve 210. Valve 210 is preferably an injection valve 100 having aninjection port 108. After optionally passing through in-line filter 212,the sample is detected in one or more continuous-flow detectors 216, 218(e.g., a light-scattering detector and/or a concentration detector).Optionally, the flow-injection system can be used as a rapidliquid-chromatography system by including a high-aspect ratio column214. The valve 210, filter 212, column 214 (if included) and detectors206, 218 can optionally be housed within a temperature-controlledenvironment (e.g., oven 208). The sample is discharged to a wastecontainer 140.

[0195] A single microprocessor (e.g., computer 222) (FIG. 7A) cancontrol the entire system 20—including sampling with the auto-sampler200, injecting of samples into the mobile phase via loading port 204,mobile-phase fluid flow via pump 116, and receiving and processing thedata from the detectors 216, 218. In an alternative configuration shownin FIG. 7B, the system 20 can be controlled with two microprocessors(e.g., computers 350, 352)—enabling high-throughput rapid-serialdetection. The robotic auto-sampler 200 and data acquisition fromdetectors 216, 218 can be controlled with the two different computers350, 252 synchronized via a trigger pulse. More specifically, computer352 can control the robotic auto-sampler 200, mobile-phase pump 116, andinjection valve 210. A serial port on the computer 352 can be connectedto a valve controller 360, which in turn can be connected to theinjection valve 210. The valve controller 360 can also be connected to apulse widening circuit 362 via a digital logic circuit (using a pulsedcontact closure). The valve controller 360 can also allow for manual(e.g., push button) operation of the valve 210, using the same digitallogic circuit. The pulse widening circuit 362 can be connected to a dataacquisition module 364 standard for chromatographic analysis. The dataacquisition module 364 can be connected to the second computer 350. Inoperation, the valve controller 360 sends a pulse signal to the dataacquisition module 364 indicating that a sample has been injected in tothe system 20, causing computer 350 to begin acquiring data from, forexample, a lighting-scattering detector 216 and a refractive-indexdetector 218 via the data acquisition module 364. The computer 352 caninclude a time variable appropriate for the characterization methodbeing employed to space the injection of samples according apredetermined interval. If a new injection pulse is sent from computer352, computer 350 can initiate new acquisition of data for the nextsample and discontinues data acquisition for the existing sample. Asimilar control configuration can be effected for liquid chromatographysystems.

[0196] The following protocols can be effectively applied individually,or in combination, and moreover, can find applications with low-,ambient-, or high-temperature characterization protocols. Although suchprotocols are primarily described with respect to polymer samples, andalthough such polymer samples are preferred samples for theflow-injection analysis protocols disclosed herein, non-polymer samplescan also be employed in some applications (e.g., pigmentcharacterization, etc.).

[0197] Flow-injection Light-Scattering

[0198] Light-scattering detectors (SLS, DLS, ELSD) can be advantageouslyapplied in flow-injection analysis applications—alone or in combinationwith other light-scattering detectors or other, non-light-scatteringdetectors. High-throughput flow-characterization methods using at leastone light-scattering technique can be referred to as “flow-injectionlight-scattering” (“FILS”).

[0199] A number of flow-injection light-scattering approaches have beendeveloped for rapidly screening polymer samples without chromatographicseparation thereof. Each of the approaches can be employed to determinepolymer properties that include average molecular weight of polymersamples (e.g., dissolved polymer samples) or average particle sizes ofpolymer samples (e.g., emulsified or dispersed polymer samples), as wellas non-averaged properties of interest. In a first method, a massdetector, such as an RI detector or an ELSD, is combined with a SLSdetector to determine the weight-average molecular weight, M_(w), of thepolymer sample—preferably of a polymer solution. In a second method, amass detector (e.g., a RI detector or an ELSD) is combined with a SLSdetector to determine particle size (e.g., volume-averaged particlediameter) of a polymer sample—preferably of a polymer dispersion oremulsion. In a third approach, a DLS detector can be used by itself todetermine an average particle size or a size distribution of a polymersample—preferably of a polymer dispersion or emulsion, or alternatively,to determine a weight-average molecular weight or a molecular weightdistribution (shape and estimate of PDI) of a polymer sample—preferablyof a polymer solution. According to a fourth approach, a SLS detectorcan be used by itself at two or more angles (typically, but notnecessarily 90° and 15° C.) to determine the radius of gyration. In yetanother approach, a SLS and DLS can be employed together to determinethe radius of gyration and the hydrodynamic radius, which can be used toprovide an indication of branching and higher-order conformation and/orarchitecture.

[0200] Some flow-injection embodiments employ other detectors—withoutlight-scattering detectors. For example, in one method, dn/dC—therelationship of refractive index and concentration of the polymersample—can be determined without chromatographic separation of polymercomponents, by measuring the response of a RI detector for samples ofknown concentration. This relationship can be effectively used, forexample, as an indicator of chemical composition of the polymer.Alternatively, in a FILS technique, more detailed information about thechemical composition of analytes can be obtained using UV-VIS orphotodiode array detector in a series with the light scattering and massdetectors. Inclusion of a viscometric detector can provide additionaluseful information about the sample, such as polymer branching.

[0201] Generally, FILS allows for the detection of both homogeneous andheterogeneous samples. FILS is optionally, and generally preferably,combined with sample pretreatment as discussed, including for example,various on-line pretreatment techniques such non-chromatographicseparation techniques with filters.

[0202] As noted above, the detector configurations employed with theabove-discussed FILS techniques can, in preferred embodiments, beadvantageously employed in combination with a very quick chromatographicseparations using the relatively high-aspect ratio column geometriesand/or targeted-separation approaches described above. Quickchromatographic separation for macromolecule or particle size separationor for separating high-molecular weight (large) particles or moleculesfrom low-molecular weight (small compounds) are preferred in combinationwith the FILS detector configurations. The speed of characterizationmethods of the invention that use capillaries, columns, and cartridgesof low volumes of 0.1-1 mL and high flow rates upwards of 20 mL/min canbe less than 10 seconds per sample, or less than 5 seconds per sample,and approach 1-3 seconds per sample.

[0203] The nature of the polymer samples and analysis technique willinfluence whether a short column, filter, or pulse damper is employed.For example, an array of solutions comprising pure polymers with nosignificant presence of large particulates or small molecules can berapidly characterized for M_(w) by the FILS methods of this invention,using an RI and SLS detector, without a chromatographic column and insome cases, also without a filter.

[0204] FILS can also be combined with variable-flow injection analysistechniques (discussed below) with or without separation or otherpretreatment.

[0205] Variable Flow Light-scattering

[0206] In another preferred approach, the flow-rate of the mobile phaseis controlled such that an injected polymer sample is rapidly advancedto and/or rapidly passed away from the detection cavity of aflow-through detector, and such that the polymer sample is slowed orstopped while the sample resides in the detection cavity of alight-scattering detector. In such variable-flow (also referred to as“stop-and-go”) techniques, the polymer sample remains slowed or stoppedduring a period of time sufficient for detection/characterization. Thisapproach can have a significant impact on the injection-to-detection runtime for a single polymer sample, and the effect is particularlysubstantial for characterizing a plurality of samples.

[0207] When the variable-flow light-scattering protocols are applied toa plurality of polymer samples, such as a library of polymer samples,the average sample-throughput can be greatly improved over constant-flowlight-scattering systems. More particularly, a plurality of polymersamples can be characterized by serially injecting a plurality ofpolymer samples into a mobile phase of a continuous-flowlight-scattering detector, advancing the injected samples toward adetection cavity of the detector, detecting light scattered from theinjected samples or from a component thereof in the detection cavity,flushing the samples from the detection cavity after detecting thescattered light, passing the flushed sample away from the detectioncavity, and controlling the flow-rates of the samples during the stepsof injecting, advancing, detecting, flushing and/or passing such thatthe average sample throughput is not more than about 10 minutes persample, preferably not more than about 4 minutes per sample, morepreferably not more than about 2 minutes per sample, and most preferablynot more than about 1 minute per sample. In some applications, theaverage sample throughput can be preferably not more than about 50seconds per sample, more preferably not more than about 40 seconds persample, even more preferably not more than about 30 seconds per sample,more preferably yet less than about 20 seconds per sample and mostpreferably less than about 10 seconds per sample.

[0208] Although the flow of the mobile phase can be temporarily stoppedaccording to one or more variations of this method, the methods, and theflow-injection systems and detectors employed are considered,nonetheless, to be continuous-flow systems and detectors. Moreover,while this variable-flow light-scattering detection approach has primaryapplications with respect to a flow-injection analysis system, ananalogous approach can be applied in connection withliquid-chromatography systems, with accommodations made, for example,for maintaining an appropriate, typically constant flow-rate through thechromatographic column.

[0209] According to one variation of the method, a polymer sample israpidly advanced to the detection cavity of a light-scattering detector,and then slowed or stopped for detection therein. Such a variation willbe referred to herein as a rapid-advance, slow-detect approach. Morespecifically, a polymer sample can be characterized by injecting apolymer sample into a mobile phase of a continuous-flow light-scatteringdetector, and advancing the injected sample is advanced toward adetection cavity of a light-scattering detector. The sample-containingmobile phase has a advancing flowrate, V_(ADVANCE), while the injectedsample is advanced toward the detection cavity. The flowrate of thesample-containing mobile phase is subsequently reduced to a relativelylower detection flowrate, V_(DETECT). The light scattered from theinjected sample or from a component thereof is detected in the detectioncavity of the detector while the mobile-phase flowrate is reduced to thedetection flowrate, V_(DETECT). The sample is then flushed from thedetection cavity after the scattered light is detected.

[0210] Following detection, the polymer sample can be passed away fromthe detection cavity at the same slower detection rate or, alternativelyand preferably, at an increased rate. That is, the rapid-advance,slow-detect approach can be followed by either a slow-pass, or arapid-pass approach. Preferably, the overall approach is arapid-advance, slow-detect, rapid-pass approach. More specifically, theflowrate of the sample-containing mobile phase is increased to a passingflowrate, V_(PASS), after detecting the scattered light, and the flushedsample is passed away from the detection cavity of the light-scatteringdetector at the passing flowrate, V_(PASS). Preferably, the passingflowrate, V_(PASS), can be substantially the same as the advancingflowrate, V_(ADVANCE) (accounting for normal variations in flow-controlcapabilities).

[0211] In an alternative variation of the method, an injected polymersample is detected in a detection cavity of a light-scattering detectorat a relatively slow flow-rate (or while stopped), and then rapidlypassed away from the detection cavity. Such a slow-detect, rapid-passvariation is more specifically described as follows. A polymer sample ischaracterized by injecting the polymer sample into a mobile phase of acontinuous-flow light-scattering detector. Light scattered from theinjected sample or from a component thereof is detected in a detectioncavity of the detector. The sample-containing mobile phase has adetection flowrate, V_(DETECT), while the scattered light is detected.The sample is flushed from the detection cavity after detecting thescattered light. The flowrate of the sample-containing mobile phase isincreased to a higher passing flowrate, V_(PASS), after detecting thescattered light, and the flushed sample is passed away from thedetection cavity of the detector at the increased higher passingflowrate, V_(PASS). The flow-rate of the mobile phase while the sampleis being advanced can be relatively slow, or fast, such that the overallapproach is slow-advance, slow-detect, rapid-pass, or rapid-advance,slow-detect, rapid-pass.

[0212] Hence, in a most preferred approach, a plurality of polymersamples are characterized by withdrawing a polymer sample from a samplecontainer. The withdrawn polymer sample is injected into a mobile phaseof a continuous-flow light-scattering detector while the mobile phasehas a advancing flowrate, V_(ADVANCE). The injected first sample isadvanced toward a detection cavity of the detector while maintaining theflowrate of the mobile phase at the advancing flowrate, V_(ADVANCE). Theflowrate of the mobile phase is then reduced to a detection flowrate,V_(DETECT). Light scattered from sample or from a component thereof isdetected in the detection cavity of the detector while the mobile phaseflowrate is at the reduced detection flowrate, V_(DETECT). The firstsample is flushed from the detection cavity after detecting thescattered light, and the flowrate of the mobile phase is increased tothe advancing flowrate, V_(ADVANCE), after detecting the scatteredlight. The flushed sample is passed away from the detection cavity ofthe detector while maintaining the flowrate of the mobile phase at theadvancing flowrate, V_(ADVANCE). The aforementioned steps can then berepeated for a plurality of polymer samples.

[0213] For any of the above protocols, when a plurality of polymersamples are being characterized with a variable-flow light-scatteringapproach, the timing of injection of a successive (e.g., second) polymersample can vary relative to the position of the preceding (e.g., first)polymer sample. More specifically, a second polymer (successive) samplecan be injected into the mobile phase of the continuous-flowlight-scattering detector at various times after the first (preceding)sample has been injected. In one variation, the second polymer sample isinjected while the first polymer sample is being passed away from thedetection cavity of the light-scattering detector. In another variation,the second polymer sample is injected while the light scattered from thefirst polymer sample is detected (that is, while the first polymersample resides in the detection cavity). In yet a different variation,the second polymer sample is injected while the first polymer sample isadvanced toward the detection cavity of the light-scattering detector.The preferred approach with respect to the timing of the injection of asecond, successive sample in a plurality of polymer samples canvary—particularly depending on the sample size, the sustainable samplingthroughput, and the actual flow-rates of the mobile phase—for advancingflow-rates, detection flow-rates, passing flowrates, and/or higherflowrates.

[0214] The polymer sample is not narrowly critical and can, in general,be a polymer sample as described above. Preferred applications of thevariable-flow light-scattering detection protocol include polymersamples comprising a polymer component having a particle that hasdiffusional mobility in the system mobile phase. Typical particle sizes(diameters) range, in typical mobile-phase solvents, from about 1 nm toabout 500 nm and preferably from about 5 nm to about 300 nm. Theseranges of particle size could be extended by changing the viscosity ofthe mobile phase, for DLS-detected systems, since DLS measuresdiffusion. The concentration of the polymer sample can generally be thesame as described above, except that the lower limits may be extended toas low as detectably possible—sufficient to scatter a light signal.

[0215] The ratio of flow-rates and the actual flow-rates employed inconnection with any variation of this approach are not critical. Ingeneral, however, advancing flowrate, V_(ADVANCE), is greater than thedetection flowrate, V_(DETECT), by a factor of at least about two, morepreferably by a factor of at least about five, and even more preferablyby a factor of at least about ten. The advancing flowrate, V_(ADVANCE),can range, for example, from about 1 ml/min to about 25 ml/min,preferably from about 1 ml/min to about 10 ml/min, more preferably fromabout 1 ml/min to about 5 ml/min and even more preferably, from about 1ml to about 3 ml. The first flowrate is most preferably about 1.5ml/min. The detection flowrate, V_(DETECT), can range from about zero toabout 1 ml/min, and preferably ranges from about 0.1 ml/min to about 0.5ml/min, and more preferably, from about 0.1 ml/min to about 0.3 ml/min.

[0216] The continuous-flow light-scattering detector can be astatic-light-scattering (SLS) detector or a dynamic-light-scattering DLSdetector. In preferred embodiments, both a SLS detector and a DLSdetector can be employed, with the SLS being used primarily forflow-control purposes, and the DLS detector data being used fordetermining a characterization property of interest (e.g.,weight-average molecular weight, particle size distribution, molecularweight distribution or other property derivable from the distribution ofthe diffusion constant). For flow-injection analysis systems having aDLS detector, the detection flowrate is preferably a constant flowrateduring the period of time when the polymer sample or a component thereofis detected. For systems having a DLS detector or a SLS detector, theflow through the detection cavity is preferably non-turbulent.

[0217] Control of the flowrates can be effected by a number of differentcontrol schemes. According to one control approach, the advancingflowrate, V_(ADVANCE), is reduced to the detection flowrate, V_(DETECT),when a leading edge of the polymer sample enters the detection cavity ofthe light-scattering detector. The detection flowrate, V_(DETECT), isthen maintained for a detecting period of time ranging from about 1second to about 60 seconds or for a period of time ranging from about 3seconds to about 40 seconds. The detecting period more preferably rangesfrom about 5 seconds to about 20 seconds, even more preferably fromabout 7 seconds to about 15 seconds, and most preferably from about 10seconds to about 12 seconds. As noted, the leading edge can be detectedwith a static-light scattering detector or a dynamic light-scatteringdetector signal that causes a change in a detector output signal (e.g.,scattered-light intensity, voltage), thereby indicating the presence ofthe polymer sample in the detection cavity. The leading edge can also bedetected with other detectors, such as an ELSD, or RI detector. Theaforedescribed control approach is represented schematically in FIG. 7D.(See also Ex. 24). A preferred In an alternative control scheme, thetiming for lowering the flowrate from the advancing flowrate to thelower detection flowrate can be based entirely on system mechanics:primarily flow-rates and residence times in the flow path. The detectingperiod is preferably sufficient to obtain scientifically meaningfuldata. The flush-out period can be a predetermined period (e.g., fromabout 5 seconds to about 10 seconds) or can be controlled based ondetector output, results, etc.

[0218] In one configuration, a continuous-flow light-scatteringdetection system for effecting the variable-flow light-scatteringprotocols comprises, with reference to FIG. 2B, an injection valve 100having an injection port 108, optionally a loading port 204 (FIG. 7) influid communication with the injection port 108 via a transfer line 206(FIG. 7), for injecting a sample into the mobile phase. The system 20also comprises a light-scattering detector 130 having a detection cavity131. The detection cavity 131 has an in inlet port and an outlet portthrough which a sample-containing mobile phase can flow. A mobile-phasefluid source (e.g., reservoir 114) is in fluid communication with theinlet port of the detection cavity, and a pump 116 provides the motiveforce for flow of the mobile phase from the source to the detectioncavity 130. The system 20 further comprises, a detector (not shown) forindicating the position of an injected sample relative to the detectioncavity, and a flow-control element (not shown) for controlling theflowrate of the mobile phase. A flow-controller is preferably incommunication with the detector and with the flow-control element. Flowcan be initiated by a pump or by the auto-sampler, optionally using aninjection valve 100 (valve 210) similar to that described above in FIG.3. In the embodiments that use a pump, the pump would be connected tothe valve at the inlet port 101. If no pump is used, the inlet port 101is plugged and the liquid medium is provided by the sampler through theloading port 204, preferably with volume control of the injected sample.

[0219] High-temperature Characterization

[0220] A number of commercially important polymers are preferablycharacterized at temperatures above room temperature. For example,polymers that are insoluble at room temperatures, but soluble at highertemperatures in a particular solvent, can be conveniently characterizedat such higher temperatures. Exemplary polymers that can becharacterized at temperatures above about 75° C. includeaqueous-associated or physically-gelling polymers (e.g., gelatin,polyvinyl alcohols). Some polymers are preferably characterized at evenhigher temperatures—above about 125° C., including for example,polyethylene (typically about 130° C.), polypropylene (typically about150° C.) and polyphenylenesulfide (typically about 200° C.).

[0221] Accordingly, a number of methods, systems and devices have beendeveloped to effect high-temperature characterization of single polymersamples and/or of a plurality of polymer samples. As used herein, theterm “high-temperature characterization” refers to characterization of apolymer sample at temperatures that are above about 75° C. and typicallyranging from about 75° C. to about 225° C., or highertemperatures—limited by the integrity of the separation medium andmobile phase at such higher temperatures. For manycommercially-important polymers, high-temperature characterization canbe effected at temperatures ranging from about 100° C. to about 200° C.,or from about 125° C. to about 175° C. Methods, systems and devices arediscussed below that relate to improved aspects of polymer sampling,chromatographic separation and detection for high-temperaturecharacterization. Those methods, systems and devices that are directedto polymer sampling or detection will have applications for flowcharacterization systems generally (i.e., for both liquid chromatographysystems and flow-injection analysis). Moreover, while the approachesdiscussed below are advantageous in connection with high-temperaturecharacterization, some of the approaches have applications outside ofhigh-temperature characterization, and, therefore, should not becategorically limited to high-temperature applications unlessspecifically required by the claims. Likewise, while some of theapproaches are described in connection with characterizing a singlepolymer, they can be and for many applications are preferably, likewiseapplicable to characterizing a plurality of polymer samples.

[0222] Auto-sampling with an External, Heated Injection Probe

[0223] Automated sampling of polymer samples for high-temperaturecharacterization is preferably effected with an auto-sampler having aheated injection probe (tip). With reference to FIG. 4 and to FIGS. 5Athrough 5C, such an auto-sampler can comprise a probe 201 mounted on asupport arm 203, a microprocessor 222 for controlling three-dimensionalmotion of the probe between various spatial addresses, and a pump (notshown) for withdrawing a polymer sample into the probe. The probe 201has a surface defining a sample-cavity 2014 and a sampling port 2016 forfluid communication between the sample cavity 2014 and a polymer sample20. The probe also preferably comprises a solvent port 2015 for fluidcommunication between a solvent supply reservoir and line (not shown)and the sample cavity 2014. The probe 201 is adapted for fluidcommunication with an injection port 108 or a loading port 204 of acontinuous-flow polymer characterization system. Significantly, theauto-sampler further comprises a temperature-control element 211 inthermal communication with the auto-sampler probe 201 for maintaining adrawn polymer sample residing in the probe at a predeterminedtemperature or within a predetermined range of temperatures—preferably atemperature of not less than about 75° C., or if necessary, not lessthan about 100° C. or not less than about 125° C. Thetemperature-control element 211 can be, in the general case, a heatingelement or a cooling element (for low-temperature characterizations).The particular design of the heating element or cooling element is notcritical. With reference to FIGS. 5A through 5B, the heating element 211can be, for example, a resistive-heating element such as a resistivewire 213 in adjacent proximity to the sample cavity 2014 of the probe201 (FIG. 5A). The heating element 211 can alternatively be a fluid-typeheat-exchanger heating element having a fluid-containing tubular coil215 around the probe 201 (FIG. 5B). In any case, thetemperature-controlled probe 201 can have a body 2012 encasing theheating element 211, and preferably a thermocouple 2018 for temperaturemonitoring and control. In another alternative embodiment, withreference to FIG. 5C, the heating element 211 can be the body 2012 ofthe probe itself, where the body 2012 comprises a large thermal mass,preferably surrounded by an insulator 2020. The large-thermal-mass body2012 can be heated (or in the general case, cooled) by periodicallyallowing the body to thermally equilibrate with a hot environment suchas a surface or fluid via conduction, convection or thermal radiation(or generally, with an cold environment).

[0224] Advantageously, such a heated probe can maintain the sample atthe required temperature while the sample resides in the sample-cavityof the probe. As such, unlike conventional high-temperaturecharacterization systems, the auto-sampler probe, as well as associatedrobotic support arm, can be located external to (outside of) a heatedenvironment (e.g., oven).

[0225] Hence, referring to FIG. 6, a polymer sample 20 can becharacterized by withdrawing a polymer sample from a sample containerinto a heated auto-sampler injection probe 201. The heated probe 201and, typically, the sample container (e.g., a library of polymer samples106) are resident in a first environment maintained at about ambienttemperature—external to a heated second environment (e.g., oven 112)maintained at a temperature of not less than about 75° C., in whichother components (e.g., chromatographic column 102) of thechromatographic system 10 reside. The polymer sample 20 is maintained,generally, at a temperature of not less than about 75° C. during aperiod of time including from when the sample is withdrawn from thesample container to when the sample is within the heated secondenvironment. In some applications, such as for flow-injection analysis,the sample is preferably maintained at a temperature of not less thanabout 75° C. during a period of time including from when the sample iswithdrawn from the sample container to when the property of the sampleor of a component thereof is detected. More specifically, the samplecontainer, if external to the second heated environment, is preferablyheated to maintain the polymer sample at a temperature of not less thanabout 75° C. while the sample is resident in the container. Theinjection probe is likewise heated to maintain the withdrawn sample at atemperature of not less than about 75° C. while the sample is residentin the probe 201. A preparation station comprising one or morepreparation containers can also be heated to the requiredhigh-temperatures.

[0226] At least a portion of the withdrawn, high-temperature sample isloaded into an injection port 108 of a flow characterization system(e.g., a liquid chromatography system or a flow-injection analysissystem), either directly or through a loading port 204 and a transferline 206. The injection port is adaptable for fluid communication with adownstream elements (e.g., chromatographic column 102 and/orcontinuous-flow detector 230), and can reside internal to or external tothe heated second environment. If the injection port resides external tothe heated second environment—in the first, near-ambient environment—theinjected sample is preferably advanced (e.g., toward the chromatographiccolumn) through a transfer line providing fluid communication betweenthe injection port and the chromatographic column and/or detector 230while heating the transfer line to maintain the injected sample at atemperature of not less than about 75° C. while resident in the transferline. In a preferred sample loading configuration, a sample can beloaded with an external auto-sampler 104′ by inserting the probe 201 ofthe auto-sampler 104′ through an aperture 113 in the heated-environmentenclosure (e.g., oven 112) and into a loading port 204 within the heatedenvironment. In such a configuration, the probe 201 can be sufficientlylong to reach into the loading port 204 within the heated environment.The loaded sample is, in any case, injected into a mobile phase of theflow characterization system. If the flow characterization system is aliquid chromatography system 10, the sample is chromatographicallyseparated. If the flow characterization system is a flow-injectionanalysis system, the sample is optionally filtered. In any case, aproperty of the sample or of a component thereof is then detected withone or more detectors 130, 132.

[0227] For polymer samples being characterized at even highertemperatures, the injection probe can be heated to maintain thewithdrawn sample at a temperature of not less than about 100° C., or ifnecessary, not less than about 125° C., while resident in the injectionprobe. The heated second environment can be maintained at a temperatureof not less than about 100° C., or, if necessary, not less than about125° C. The sample is, in such cases, respectively maintained at atemperature of not less than about 100° C., or if necessary, not lessthan about 125° C., during the period of time including from when thesample is withdrawn from the sample container to when the sample isinjected into the portion of the flow characterization system (e.g.,liquid chromatography system) residing in the heated second environment.

[0228] Rapidly Heated/Cooled Column and System

[0229] According to another high-temperature characterization protocol,a polymer sample can be characterized in a liquid chromatography systemthat is readily adapted to high-temperature characterization protocols.Specifically, a chromatographic column is prepared for separation byheating the column from about ambient temperature to about 75° C. inless than about 1 hour. A polymer sample is injected into the mobilephase of the liquid chromatography system and loaded onto the heatedcolumn. At least one sample component of the polymer sample ischromatographically separated from other sample components thereof inthe heated chromatographic column, and a property of at least one of theseparated sample components is then detected.

[0230] If necessary for a particular application, the chromatographiccolumn can be heated from about ambient temperature to about 100° C., oralternatively, to about 125° C. in less than about 1 hour. Higher ratesof heating can also be employed, as necessary. For example, thechromatographic column can be heated from about ambient temperature toabout 75° C., or if necessary, to about 100° C. or to about 125° C. inless than about 30 minutes. Advantageously, the chromatographic columncan be readily cooled back to ambient temperatures at similar rates,such that the system is prepared for lower-temperature characterization.

[0231] In a preferred embodiment for this characterization protocol, thechromatographic column is preferably the relatively high-aspect ratiochromatographic column discussed above. The relatively low mass of sucha column enables it to be rapidly heated (and/or cooled) relative toconventional columns employed for high-temperature characterization.Additionally, the detector can be a temperature-insensitive detector,such as described below, that can reside external to a heatedenvironment. In such liquid chromatography systems, the column can bethe only component thereof in the heated environment. Hence, the liquidchromatography system, as a whole, can be rapidly prepared forhigh-temperature characterization, and if desired, rapidly convertedback to ambient-temperature conditions.

[0232] Mobile Phase Composition Gradient

[0233] In a further high-temperature characterization protocol, apolymer sample can be characterized in a liquid chromatographic systemthat employs a compositional gradient to the mobile phase forselectively eluting one or more components of polymer sample from thechromatographic column. While such an approach has been employed inconnection with ambient-temperature systems, methods and apparatus forhigh-temperature liquid chromatography with a mobile-phase compositionalgradient have not been heretofore employed.

[0234] Hence, in a preferred approach, a polymer sample can becharacterized by loading the polymer sample onto a chromatographiccolumn, and maintaining the loaded polymer sample at a temperature ofnot less than 75° C. One or more sample components of the loaded polymersample are then eluted with a mobile-phase eluant having a temperatureof not less than about 75° C. while the composition of the mobile-phaseeluant is controlled to vary over time to separate at least one samplecomponent of the sample from other sample components thereof. A propertyof at least one of the separated sample components is detected. Asdesired, the loaded polymer sample can be maintained at a temperature ofnot less than 100° C., or not less than about 125° C., and themobile-phase eluant can have a temperature of not less than about 100°C., or not less than about 125° C.

[0235] With reference to FIG. 6, such a preferred mobile-phase gradientapproach can be effected with a liquid chromatography system 10comprising an enclosure defining a heated environment (e.g. oven 112),where the heated environment is maintained at a temperature of not lessthan about 75° C. A chromatographic column 102 resides in the heatedenvironment. The chromatographic column 102 can comprise a surfacedefining a pressurizable separation cavity, an inlet port for receivinga mobile phase and for supplying a polymer sample to the separationcavity, an effluent port for discharging the mobile phase and thepolymer sample or separated components thereof from the separationcavity, and a stationary-phase within the separation cavity. The system10 also comprises an injection valve 210 (100) having one or moreinjection ports 108 adaptable for fluid communication with thechromatographic column 102 for injecting polymer samples into the mobilephase. The system 10 further comprises two or more reservoirs and pumpsadequate to establish a mobile-phase compositional gradient—morespecifically, a first reservoir 114 containing a first mobile-phasefluid, and a second reservoir 120 containing a second mobile-phasefluid. First and second pumps 116, 118 are dedicated to first and secondreservoirs, 114, 120, respectively. The system 10 also comprises one ormore mixing zones 144 adapted for or adaptable for fluid communicationwith the first reservoir 114 and the second reservoir 120 for mixing ofthe first and second mobile-phase fluids to form a mobile-phase eluanthaving compositions (and/or temperatures) that can vary over time. Theone or more mixing zones 144 are further adapted for or adaptable forfluid communication with the inlet port of the chromatographic column102 for eluting one or more sample components of the sample with themobile-phase eluant to separate at least one sample component of thesample from other sample components thereof. One or more detectors 130,132 are in fluid communication with the effluent port of thechromatographic column 102 for detecting a property of at least one ofthe sample components.

[0236] The system 10 can optionally comprise a third reservoir and/or afourth reservoir (not shown) having a third and/or a fourth dedicatedpump, respectively) for containing a third and/or a fourth mobile-phasefluid, with such third and/or fourth reservoir being adaptable for fluidcommunication with a mixing zone for mixing of the third and/or fourthmobile-phase fluid with one or both of the first or second mobile-phasefluids. Each of the reservoirs 114, 120 and associated pumps 116, 118are preferably isolable from each other, for example, with valves 124.

[0237] The location of the one or more mixing zones 144 within theliquid chromatography system 10 is not narrowly critical. The mixingzones 144 can be, for example, directly upstream of the inlet port tothe chromatographic column 102. In another embodiment, the mixing zone144 can be located in a mobile-phase column-supply line upstream and/ordownstream of the injection valve 100. In a further embodiment, thechromatographic column 102 can comprise two inlet ports, each of whichis in fluid communication with a different mobile-phase reservoir 114,120, 129, and the mixing zone is within the chromatographic column 102.

[0238] Mobile-phase Temperature Gradient

[0239] In yet another polymer characterization protocol, a polymersample can be characterized in a liquid chromatographic system thatemploys a temperature gradient to the mobile phase for selectivelyeluting one or more components of polymer sample from thechromatographic column. While such an approach may have primaryapplications in connection with high-temperature polymercharacterization, the protocols can also be advantageously employed inconnection with ambient-temperature and/or cold-temperature protocols.

[0240] According to one method for characterizing a polymer sample, apolymer sample is loaded onto a chromatographic column. One or moresample components of the loaded polymer sample are eluted with amobile-phase eluant while the temperature of the mobile-phase eluant iscontrolled to vary over time to separate at least one sample componentof the sample from other sample components thereof. A property of atleast one of the separated sample components is detected.

[0241] In practice, such a method can be used forprecipitation-redissolution chromatography or adsorption chromatographywhere the solubility or adsorptivity of the polymer sample componentsare controlled by mobile-phase temperature—alone or in combination witha change in mobile-phase composition. Briefly, a polymer sample isinjected into a mobile phase having a temperature less than thetemperature at which one or more components of the polymer sample (e.g.,a polymer component, a monomer component) are soluble or not adsorbed,such that the one or more polymer sample components precipitate andforms a separate gel-phase or become adsorbed—typically depositing ontothe stationary-phase media of the column. The temperature of the mobilephase is then gradually increased such that the one or more precipitatedor adsorbed components will selectively redissolve into the mobile phasebased on its respective solubility therein. Since thetemperature-dependence of the solubility or adsorptivity is a functionof both molecular weight and the particular chemistry of the component,meaningful resolution of polymer sample components and molecular-weightdistributions can be obtained.

[0242] In preferred applications, therefore, the polymer samplepreferably comprises at least one precipitated sample component afterbeing loaded onto the chromatographic column. For high-temperaturecharacterization applications, the polymer sample can comprise one ormore sample components that are insoluble at a temperature of less thanabout 75° C., or alternatively, at a temperatures of less than about100° C., or of less than about 125° C. Moreover, because desorption fromthe stationary-phase of the column is based on selectiveresolubilization of sample components, one or more sample components arepreferably non-desorbing from the stationary-phase media at atemperature of less than about 75° C., or alternatively, at atemperatures of less than about 100° C., or of less than about 125° C.

[0243] The method described in the immediately-preceding paragraphs canbe advantageously effected with a liquid chromatography system such asis depicted in FIG. 6, and described above in connection with liquidchromatography based on mobile-phase compositional gradients. Referringto FIG. 6, a mobile-phase temperature gradient can be achieved over timeby heating a first reservoir 114 to maintaining a first mobile-phasefluid at a first (e.g., hot) temperature, and heating a second reservoir120 to maintaining a second mobile-phase fluid at a second (e.g., cold)temperature that is different from the first temperature. Thetemperature of the mobile phase supplied to the column 102 can then becontrolled by varying the relative amounts of the first and secondmobile-phase fluids supplied to a mixing zone 144. For high-temperaturecharacterization applications, where the column 102 resides in a heatedenvironment (e.g., oven 112), a mixing zone 144 is preferably situatedimmediately upstream of the inlet port to the column 102, and moreover,the system 10 preferably has a short transfer line from a reservoir(e.g., the third reservoir 129) to the mixing zone 144, such that thetemperature-normalizing effects of the heated environment are minimized.

[0244] More generally, a liquid chromatography system for effectingseparation with a mobile-phase temperature gradient can comprise,referring to FIG. 6, a chromatographic column 102, and an injectionvalve 100 having one or more injection ports 108. The system 10 alsocomprises a reservoir (e.g., 114) for containing a mobile-phase fluid.The reservoir is adapted for or adaptable for fluid communication withthe inlet port of the chromatographic column. The system 10 furthercomprises a heater for controlling the temperature of the mobile-phasefluid such that one or more sample components of the polymer sample canbe eluted with a mobile-phase fluid having a temperature that variesover time to separate at least one sample component of the sample fromother sample components thereof, and a detector in fluid communicationwith the effluent port of the chromatographic column for detecting aproperty of at least one of the sample components.

[0245] The particular design for the mobile-phase heater is notcritical. The heater can be, for example, an enclosure defining a heatedenvironment (e.g., oven 112) in which the chromatographic columnresides, or alternatively, in which a length of a mobile-phase fluidtransfer line resides. In some cases, the heated environment can bemaintained at a temperature of not less than about 75° C., oralternatively, not less than about 100° C., or not less than about 125°C. The heater can also be a heating element (e.g. resistive-heatingelement or a fluid-heat-exchanger) in thermal communication with thereservoir, or alternatively, in thermal communication with amobile-phase fluid transfer line.

[0246] Column/Stationary-phase Temperature Gradient

[0247] In a related, alternative approach, the solubility of a polymersample component can be controlled with temperature to effect achromatographic separation by controlling the temperature of thechromatographic column directly—through a temperature-control elementssuch as heating and/or cooling elements. The temperature of the columnand its stationary-phase media can be directly controlled eitheralternatively to or in addition to controlling the temperature of themobile phase. In preferred embodiments, the temperature of the columnand/or stationary-phase are controllably varied while maintaining thetemperature of the mobile phase approximately constant. Moreover, thetemperature of the column and/or stationary-phase can be controllablyvaried not only with time, but also with relative position over thelength of the column.

[0248] Hence, in another preferred protocol, a polymer sample can becharacterized by loading a polymer sample onto a chromatographic column.The loaded sample is then eluted with a mobile-phase eluant. Thetemperature of the column and/or stationary-phase is controllablyvaried—directly by a temperature control element in thermalcommunication with the column—while eluting the column with themobile-phase eluant, such that at least one sample component of theloaded sample is separated from other sample components thereof. Aproperty of at least one of the separated sample components is detected.

[0249] The mobile-phase eluant can be supplied to the column at atemperature that is constant over time or alternatively, that variesover time. To effect precipitation of a sample component in aprecipitation-redissolution chromatographic separation, the temperatureof the column can also be directly controlled while loading the sampleonto the column, such that at least one sample component precipitates oradsorbs onto the stationary-phase media.

[0250] A number of system configurations can be employed to achievedirect temperature control of the chromatographic column. Preferably,for example, the temperature of the column is directly controlled with atemperature-control element in direct thermal communication with thecolumn. The temperature-control element can be a heating element or acooling element. Exemplary temperature-control elements can include, forexample, a resistive-heating element or a fluid-heat-exchanger inthermal communication with the column.

[0251] Reduced-sensitivity Detectors

[0252] In yet another polymer characterization protocol, a polymersample can be characterized in a flow characterization system (e.g.,liquid chromatographic system) that employs a detector that is lesstemperature sensitive than conventional detectors. That is, the detector(e.g., a mass detector) can encounter larger variations in sampletemperature without substantially affecting detection of a property ofinterest. Moreover, the detector preferably does not have to beequilibrated to the same temperature as the sample being characterized.A system having such a detector is advantageous in several aspects.First, a detector having a reduced temperature-sensitivity allows for agreater degree of variation of the heated environment (e.g., oven). Assuch, a less expensive heated environment can be employed. Moreover, theheated environment can be accessed, at least briefly, during ahigh-temperature characterization protocol without substantiallyimpacting the detection data. As an additional advantage, thetemperature-insensitive detector can, in some cases, be located externalto the heated environment. As such, the size of the heated environmentcan be reduced, allowing less expensive equipment. Moreover, the rate atwhich the components of the characterization system can be heated upand/or cooled down is improved, since thermal equillibration of thedetector will not be required.

[0253] Hence, a flow characterization system (e.g., liquidchromatography system 10) effective for high-temperaturecharacterization of a polymer sample can comprise, with reference toFIG. 6, a enclosure defining a heated environment (e.g., oven 112). Theheated environment is maintained at a temperature of not less than about75° C. and has at least about ±0.5° C. variation in temperature. Aliquid chromatography system 10 also comprises a chromatographic column102 residing in the heated environment. The flow characterization systemfurther comprises an injection valve 100 having one or more injectionports 108, a reservoir (e.g., 114) in fluid communication with the inletport of the chromatographic column 102 and/or with detector 130, and oneor more detectors 130 132 in fluid communication with the effluent portof the chromatographic column 102 or the injection port 108 fordetecting a property of at least one of the sample components. At leastone of the detector is insensitive to variations in temperature of about±0.5° C.

[0254] In some embodiments for the flow characterization system, theheated environment is maintained at a temperature of not less than about100° C., or alternatively, at a temperature of not less than about 125°C. Moreover, the heated environment can have a variation in temperatureof at least about ±1° C., with the detector being insensitive to thevariations in temperature of about ±1° C. Alternatively, the heatedenvironment can have a variation in temperature of at least about ±2°C., or in some applications, at least about ±5° C., with the detectorbeing insensitive to the variations in temperature of about ±2° C. or insome applications, of about ±5° C., respectively. The detector is mostpreferably an evaporative light scattering detector (ELSD). Hence, in apreferred liquid chromatography protocol, a polymer sample can becharacterized by separating at least one sample component of a polymersample from other sample components thereof in a chromatographic columnresiding in a heated environment. The heated environment is maintainedat a temperature of not less than about 75° C., while a variation in thetemperature of the heated environment of at least about of at leastabout ±0.5° C. is allowed. A property of at least one of the separatedsample components is detected with a detector insensitive to the about±0.5° C. variation in temperature of the heated environment.

[0255] In variations of the preferred protocol, the allowed variation intemperature of the heated environment can be at least about ±1° C., orin some cases, at least about ±2° C. or at least about ±5° C., and thedetector is insensitive to the about ±1° C., or in some cases, at leastabout ±2° C. or at least about ±5° C. variation in temperature of theheated environment, respectively. In any of such cases, the heatedenvironment can be maintained to be not less than about 100° C., oralternatively, not less than about 125° C.

[0256] High-temperature Flow-injection Analysis

[0257] In a preferred high-temperature flow-injection analysis protocol,a polymer sample can be characterized by serially injecting a pluralityof polymer samples into a mobile phase of a continuous-flow detector. Aproperty of the injected samples or of components thereof is detectedwith a continuous-flow detector. The polymer samples are maintained at atemperature of not less than about 75° C. during a period of timeincluding from when the samples are injected into the mobile phase ofthe continuous-flow detector to when the property of the injectedsamples or of a component thereof is detected.

[0258] In alternative approaches, the polymer samples can be maintainedat a temperature of not less than about 100° C., or of not less thanabout 125° C. during the period of time including from when the samplesare injected into the mobile phase of the continuous-flow detector towhen the property of the injected samples or of a component thereof isdetected.

[0259] Calibration Methods and Standards for Flow CharacterizationSystems

[0260] Flow characterization systems are typically calibrated usingcalibration standards having known properties. For gel permeationchromatography (GPC), for example, calibration standards comprisingknown molecular weights can be used to calibrate the GPC system.Typically, a calibration standard comprises a heterogeneous polymercomponent having a number of polymer subcomponents that differ withrespect to the calibrating property. Such subcomponents are typicallyreferred to as “known standards” or, simply, “standards” that are wellcharacterized with respect to the calibrating property of interest. Formolecular weight (or hydrodynamic volume), for example, a calibrationstandard typically comprises polymer standards having the same repeatunit, but having well-defined and well-characterized differences withrespect to molecular weight (or hydrodynamic volume).

[0261] It is generally preferred to calibrate a flow characterizationsystem with calibration standards comprising a polymer component thathas polymer molecules with the same repeat units as the as the targetpolymer molecule being characterized by the system. For example, ifpolymer samples comprising polyisobutylene polymer components are thetarget polymer samples being characterized, the calibration standardalso preferably comprises polyisobutylene polymer components.

[0262] However, because adequate standards are not generally availablefor each of the many different polymers being investigated,investigators have long employed “universal calibration” approaches. ForGPC, universal calibration is based on the premise that themultiplication products of intrinsic viscosities and molecular weights(hydrodynamic volumes) are independent of polymer type. Mark-Houwinkparameters, which describe the molecular weight dependence on intrinsicviscosity for a particular polymer, can be used to create universalcalibration plots from actual calibrations performed with availablecalibration standards such as polystyrene. Although such “universalcalibration” approaches can be used to calibrate for polymer moleculesfor which direct physical standards are not available, are difficult toobtain, are expensive and/or are unstable, such practices typicallyintroduce errors—particularly if values of intrinsic viscosities aretaken from literature rather than measured directly under the particularconditions to be use for the polymer characterization system.

[0263] Despite such inaccuracies, such “universal” standards arefrequently employed because they offer another desirableattribute—extremely narrow polydispersities that enable the convenienceof a “single-shot” calibration. That is, calibration of the flowcharacterization system can be effected by introducing a single polymersample having, and typically consisting essentially of a single polymercomponent, the polymer component comprising a number of subcomponents(e.g., standards), each of which comprises polymer molecules having thesame repeat unit but varying with respect to molecular weight(hydrodynamic volume) of those polymer molecules. However, such a“single-shot” or “one-shot” calibration approach is most practical ifthe determined molecular weight (hydrodynamic volume) distribution peaksare very narrow—with polydispersity indexes of about 1.0. Single-shotcalibration with polymer components having broad-band distributions,rather than narrow-band distributions are generally ineffective forcalibration purposes due to inadequate resolution. See, for example,FIG. 22A and Example 25. Presently, calibration standards comprisingpolymer components having narrow-band distributions are available forrelatively few types of polymer molecules, such as polystyrene—commonlyused for organic solvent systems and poly(ethylene oxide) orpoly(ethyleneglycols)—commonly used in aqueous systems.

[0264] While polystyrene or other narrow-band calibration standards canbe used directly, with molecular weights (hydrodynamic volumes) or otherproperties reported as, for example, “polystyrene-equivalent” molecularweights (hydrodynamic volumes), such an approach does not provideaccurate absolute values for the property of interest, and as such, maynot necessarily provide a meaningful basis for direct comparison betweensystems.

[0265] The options based on conventional methodologies for calibratingcharacterization systems for target polymer samples for which polymercomponents with narrow-band distributions are not available are notattractive for combinatorial polymer chemistry applications. One could(1) calibrate with a mixture of narrow-band standards comprised ofpolymer molecules having different repeat units than those of the targetpolymer sample; (2) rely on universal calibration and/or (3) performrepetitive, “multi-shot” calibration runs with calibration polymersamples consisting of a single, broader-band polymer component. Asnoted, the former alternatives have inherent inaccuracies. The latteralternative is time consuming. The latter approach can also beexpensive—particularly where repetitive calibrations are required andthe standards are not reusable, for example, due to degradation overtime and/or during the calibration process. Hence, while suchalternatives may have been acceptable for conventional polymer chemistryresearch, they are inadequate for applications that demand both accuracyand high-speed calibration at reasonable costs—such as combinatorialpolymer research applications.

[0266] Accordingly, compositions and methods are disclosed herein thatallow for accurate, rapid, “single-shot” characterization of polymercharacterization systems. The compositions disclosed herein are“single-shot” calibration standards that provide calibration accuracyequivalent to a series of “multi-shot” calibrations with polymercomponents having the target polymer being characterized.

[0267] Briefly, an indirect calibration standard of the presentinvention is a composition that consists essentially of a polymercomponent. The polymer component comprises a plurality of narrow-bandpolymer subcomponents, each of which can be a narrow-band polymerstandard. Each of the narrow-band polymer standards preferably has adifferent known molecular weight, a polydispersity index ranging fromabout 1.00 to about 1.10, and a hydrodynamic volume that issubstantially equivalent to the hydrodynamic volume of a series ofbroad-band target-polymer standards. The target-polymer standards arepreferably target-polymer standards, each having a different knownmolecular weight, and having a polydispersity index of more than about1.10. Because the polymer molecule of the narrow-band polymer standardsis different the polymer molecule of the broad-band target polymerstandards (i.e., the narrow-band polymer standards have a differentrepeat structure from the broad-band polymer standards) the actualmolecular weights of the corresponding polymer standards will bedifferent.

[0268] More specifically, an indirect calibration standard is acomposition that consists essentially of a heterogeneous polymercomponent. The polymer component comprises a plurality of first,narrow-band polymer standards (subcomponents) and a continuousliquid-phase in which the narrow-band polymer standards can bedissolved, emulsified and/or dispersed. Each of the narrow-band polymerstandards has a polydispersity index of about 1 and each comprisespolymer molecules—with the same repeat structure as, but with adifferent hydrodynamic volumes than—the polymer molecules of othernarrow-band polymer standards. Significantly, the hydrodynamic volume ofeach polymer molecule for a given standard is substantially equivalentto (i.e., the same as) the hydrodynamic volume of a corresponding targetpolymer standard molecule. Each of a plurality of target polymerstandards comprise one of the corresponding target polymer molecules.The target polymer standards are typically wide-band polymer standards,and are, in any case, preselected to include target polymer moleculeshaving the same repeat structure, but with hydrodynamic volumes thatvary over a range of hydrodynamic volumes sufficient to prepare aneffective calibration curve (e.g., molecular weight vs. retention time).The actual molecular weights of the narrow-band polymer molecules willtypically be different than the actual molecular weights of thecorresponding target-polymer molecules.

[0269] In a preferred application, for example, where the first,narrow-band polymer component is a polystyrene component, the indirectcalibration standard is a composition that comprises two or morepolystyrene standards and a continuous liquid-phase. Each of thepolystyrene standards have a polydispersity index of about 1 andcomprise polystyrene molecules having a hydrodynamic volumesubstantially equivalent to the hydrodynamic volume of a preselectedtarget polymer standards. The target polymer standards are a preferablya polymer other than polystyrene. A set of the two or moretarget-polymer standards can comprise the two or more preselectedtarget-polymer molecules. The two or more target polymer molecules arepreselected to have hydrodynamic volumes that vary over a range ofhydrodynamic volumes sufficient to prepare an effective calibrationcurve (e.g., molecular weight vs. retention time).

[0270] The number of narrow-band polymer components generallycorresponds to the number of target-polymer components, and cangenerally range from two to about ten, but can be 5 or more, or 10 ormore, and is preferably about 5. The polydispersity index of thenarrow-band polymer standards can range from about 1.0 to about 1.10,and preferably ranges from about 1.0 to about 1.05. Preferred targetpolymers include polymers for which presently available polymerstandards have a polydispersity index of less than about 1.10, are notreadily available, are prohibitively expensive and/or are not stableunder the anticipated characterization conditions. Exemplary targetpolymers include polyisobutylene, polyethylene, polybutylacrylate,polypropylene, polymethylmethacrylate, polyvinylacetate, polystyrenesulfonic acid, and polyacrylamide, among others.

[0271] The indirect calibration standards of the present invention canbe prepared as follows. In one set of steps, two or more target-polymerstandards with known molecular weights (e.g., peak molecular weightand/or average molecular weight) are serially and individually loadedinto a polymer characterization system—preferably a liquidchromatography system, and more preferably a size exclusionchromatography system. Each of the target polymer standards comprisestarget polymer molecules. Each of the target polymer molecules is apolymer other than a narrow-band polymer, preferably with apolydispersity index of more than about 1.10, and each target polymermolecule has the same repeat structure as, but a different hydrodynamicvolume than, other target polymer molecules. The hydrodynamic volume ofthe target polymer molecules is determined for each of the individuallyloaded target polymer standards (subcomponents).

[0272] In a second set of steps, performed before or after the first setof steps, two or more narrow-band polymer standards are loaded into thepolymer characterization system. Each of the loaded narrow-band polymerstandards has a polydispersity index of about 1 and comprises anarrow-band polymer molecule. Each narrow-band polymer molecule has thesame repeat structure as, but a different hydrodynamic volume than,other narrow-band polymer molecules. The hydrodynamic volume of thenarrow-band polymer molecules is determined for each of the loadednarrow-band polymer standards. After the first and second set of steps,two or more narrow-band polymer standards that comprise narrow-bandpolymer molecules having a hydrodynamic volume substantially equivalentto the hydrodynamic volume of a target polymer molecule are selected. Acomposition comprising the selected narrow-band polymer standards isthen formed. The composition preferably consists essentially of theselected narrow-band polymer standards and a continuous liquid-phase,but may include other additives, etc. for control purposes.

[0273] In an exemplary method for preparing preferred polystyrenecalibration protocols, a first target-polymer standard is loaded into apolymer characterization system. The first target-polymer standardcomprises target-polymer molecules other than the narrow-band polymer.The hydrodynamic volume of the target polymer molecules are determined.A second target polymer subcomponent is loaded into the polymercharacterization system. The second target polymer component comprisestarget polymer molecules other than polystyrene. The second targetpolymer molecules have the same repeat structure as, but a differentmolecular weight than, the first target polymer molecules. Thehydrodynamic volume of the second target polymer molecules isdetermined. Preferably, one or more additional target polymer standardsare serially loaded into the polymer characterization system. The one ormore additional target polymer standards each comprise one or moreadditional target-polymer molecules other than polystyrene. The one ormore additional target polymer molecules each have the same repeatstructure as, but a different molecular weight than, the first targetpolymer molecule, the second target polymer molecules and otheradditional target polymer molecules. The hydrodynamic volumes of the oneor more additional target polymer molecule are determined. A series ofpolystyrene standards are loaded into the polymer characterizationsystem. Each of the loaded polystyrene standards has a polydispersityindex of about 1 and comprises polystyrene molecules having a differenthydrodynamic volume than other polystyrene molecules. The hydrodynamicvolume of the polystyrene molecules is determined for each of the loadedpolystyrene standards. Polystyrene standards having polystyrenemolecules with a hydrodynamic volume substantially equivalent to thedetermined hydrodynamic volumes of the target polymer molecules areselected. A composition comprising the selected polystyrene standards(subcomponents) is then formed.

[0274] A polymer characterization system can be calibrated with theindirect calibration standards described above and/or prepared asdescribed above. Briefly, the calibration composition is loaded into apolymer characterization system. A property of the narrow-band (e.g.,polystyrene) components of the injected composition is detected and/ordetermined. A correlation is prepared by assigning the value for thedetected property of each of the narrow-band standards to thecorresponding target polymer standards.

[0275] Once a polymer characterization system has been calibrated, aplurality of target polymer samples can be screened as described herein.

[0276] Multi-system, Rapid-serial Polymer Characterization

[0277] The high-throughput rapid-serial flow characterization systemscan be advantageously applied in combination with other polymercharacterization systems for effectively and efficiently characterizinga plurality of polymer samples.

[0278] In a general case, a plurality of polymer samples, preferablyfour or more polymer samples (e.g., in a library of polymer samples) areserially screened (characterized) for a first property of interest witha first characterization system. The first characterization system hasan average sample-throughput of not more than about 10 minutes persample, and in preferred approaches, is a flow characterization system.At least one of the four or more samples screened with the firstcharacterization system is then screened for a second property ofinterest with a second characterization system. Additional screeningswith additional characterization systems can also be effected.

[0279] The second polymer characterization system can be, but is notnecessarily a flow characterization system, and moreover, can have, butdoes not necessarily have, an average sample-throughput of not more thanabout 10 minutes per sample. The first and second properties of interestcan be the same or different. The first and second characterizationsystems can likewise be the same or different. For example, eachcharacterization system can be a liquid chromatography system, each canbe a flow-injection analysis system, or one can be a liquidchromatography with the other being a flow-injection analysis system.

[0280] In one approach, the two or more characterization systems can beused to screen each of a plurality of polymer samples for two or moreproperties of interest—one property being determined by one system,another property being determined by a second system, etc. Morespecifically, each of the four or more samples screened with the firstcharacterization system can be screened for the second property ofinterest with the second characterization system.

[0281] In a preferred application of such approach, in which two liquidchromatography systems are employed, a polymer sample is withdrawn froma sample container, and a first portion of the withdrawn sample isinjected into a mobile phase of the first liquid chromatography system.A second portion of the withdrawn sample is then injected into a mobilephase of the second liquid chromatography system. Each of the injectedsamples are then separated, and a property of the samples or of acomponent thereof is detected in each of the respective systems. Thesesteps can be repeated in series for additional polymer samples.

[0282] In an alternative approach, a first characterization system canbe used to prescreen each of a plurality of polymer samples for a firstproperty of interest, and then a second characterization system can beused to rescreen certain selected polymer samples—for the same or for adifferent property of interest—with the selection for the second screenbeing based on results from the first prescreening. Briefly, four ormore samples are screened to determine a first property of interest in afirst screen. A figure of merit is determined for the four or moresamples. The figure of merit is preferably based, at least in part, onthe first determined property of interest. The determined figure ofmerit for the four or more samples is compared with a predeterminedthreshold value for the figure of merit. The threshold value can bebased, for example, on results with a then-best-known system. Thosesamples of the four or more samples that favorably compare with thepredetermined threshold value for the figure of merit are then screenedwith the second characterization system. In a preferred embodiment, onlythose samples that favorably compare to the predetermined figure ofmerit are screened with the second characterization system.

[0283] Non-flow Characterization Systems

[0284] In non-flow polymer characterization systems, the polymer sampleis detected statically without flow of the sample. With reference toFIG. 1A, non-flow characterization processes may be effected with asample preparation (steps A, D and E) or without a sample preparation(steps D and E).

[0285] For rapid screening of combinatorial libraries of polymers, is itoften not necessary to know the polydispersity index (PDT). In suchcases, parallel light scattering systems may be advantageously employed.Preferably, the polymer samples are diluted in preparation forlight-scattering detection, as described for the serial flowcharacterization approach. The preparation step can be effected in arapid-serial, a parallel or a serial-parallel manner.

[0286] In a rapid-serial embodiment, a light-scattering detector, suchas a dynamic light-scattering (DLS) detector, can be mounted on aplatform for staging over an array of polymer samples. The DLS detectorcan then serially detect the light scattered from each of the samples insequence. Automated relative motion can be provided between theDLS-platform and the array of polymer samples by robotically controllingthe DLS-platform and/or the array of sample containers.

[0287] In one parallel embodiment, an entire library of polymers can beilluminated and scattered light can be detected from every sample at thesame time. The concentration of polymer in each well may be derived inparallel by using parallel absorbency or refractive index measurements.In this embodiment, the detector can be a static light-scattering (SLS)detector or a dynamic light-scattering (DLS) detector.

[0288] In another parallel embodiment, a property of two or more polymersamples is detected simultaneously (i.e., in parallel) with two or morelight-scattering detectors positioned in appropriate relation to thesamples. In a preferred system, the light-scattering detectors aredynamic light-scattering (DLS) detectors, and preferably, fiber-opticDLS detectors. Such a system can also be employed in a pure-parallel, aserial-parallel or hybrid serial-parallel detection approach forscreening four or more polymer samples, such as a combinatorial libraryof polymerization product mixtures arranged in an array of samplecontainers. Here, two or more DLS detectors can be mounted on a commonplatform for staging over the array of polymer samples. The two or moreDLS detectors can detect the light scattered from two or more of thesamples in parallel, and then the DLS-platform (or the array) can bemoved such that the two or more DLS detectors can be serially advancedto the next subset of polymer samples. Automated relative motion can beprovided between the DLS-platform and the array of polymer samples byrobotically controlling the DLS-platform and/or the array of samplecontainers. The number of DLS probes employed in the system can rangefrom 2 to the number of polymer samples included within a plurality ofpolymer samples (as generally discussed above).

[0289] A preferred configuration thereof can be a non-flow, immersion ornon-immersion parallel DLS configuration. Briefly, with reference toFIG. 24, a parallel DLS system can comprise an array 410 of two or moreDLS probes 420, 420′, 420″ configured in a spatial relationship withrespect to each other. Each probe 420, 420′, 420″ can include atransmitting optical fiber 425, 425′, 425″ and a receiving optical fiber430, 430′, 430″. Although shown in FIG. 24 as being immersed, the probes420, 420′, 420″ can also be positioned over the samples of interest in anon-immersed configuration. Each probe 420, 420′, 420″ further comprisesa single-mode fiber coupler, also referred to as an optic (not shown),suitable for transmitting incident light to a sample and/or collectingscattered light from a sample. These couplers can preferably consist,for example, of a gradient refractive index (GRIN) lens aligned to asingle-mode optical fiber—and be mounted at an angle of 45 degrees withrespect to each other to provide for a measurement angle of 135 degrees.Other couplers and/or configurations known in the art can also beeffectively employed. A laser light can be provided from laser 435 andcoupled into the transmitting optical fibers 425, 425′, 425″ by means ofthe fiber-optics array 440. The coupled laser light can be deliveredinto the sample 20 and scattered by one or more particles of the polymersample. The scattered light can be collected via one or more optics, asdescribed above, and coupled into the receiving optical fiber 430, 430′,430″. The receiving optical fiber 430, 430′, 430″ can be in opticalcommunication with a detector array 450 (e.g., an array of avalanchephotodiodes (APD)). Measurements and photon autocorrelation can be takenin a serial manner using commercially-available autocorrelator boards,such as the ALV 5000IE (ALV GmbH, Langen, Germany). The hydrodynamicradius, R_(h), and the polydispersity index (PDI) can be determined fromthe detected scattered light with commercially-available software. Othersuitable configurations can also be arranged by a person of skill in theart.

[0290] In each of the aforementioned embodiments, the light-scatteringdetector can, depending on its design characteristics, be immersed inthe polymer sample during detection or, alternatively, be positionednear the surface of the polymer sample for detection without immersiontherein.

[0291] The following examples illustrate the principles and advantagesof the invention.

EXAMPLES Example 1 Auto-sampling with Single Robotic Arm

[0292] This example demonstrates rapid, automated (robotic) preparationand sampling of polymer libraries using one robotic arm.

[0293] Conventional, Commercially-available Auto-sampler

[0294] A conventional, commercially-available auto-sampler wasevaluated. A Gilson®, (Middleton, Wis.) Model 215 is described byGilson® as a computer-controlled XYZ robot with stationary rack. It wasmounted with a steel needle probe, a syringe pump, and a valve andsample loop connected to an HPLC system. This auto-sampler, asprogrammed by Gilson®, required slightly more than 90 seconds to performthe following sequence of operations: (1)drawing 100 μL water fromposition 1 of a microtiter plate; (2) loading a 50 μL sample loop withthe water; (3) actuating the injection valve to inject the sample intothe flow system; (4) cleaning the probe needle by flushing inpreparation for the next sample; and (5) repeating steps (1) through (4)with water from a second position 2 of the same microtiter plate. TheGilson auto-sampler's computer interface did not allow the user toprogram a new sample container (e.g., reactor block or sample block)configurations—geometries or locations. Also, the robotic arm speed wasnot controllable, and the probe was incapable of liquid level-sensing.

[0295] Auto-sampler of the Invention

[0296] The following describes the design and operation of theauto-sampler 200, probe 201, loading port 204, and injection valve 210(100) shown in FIG. 4 and discussed in connection therewith.

[0297] A programmable XYZ robotic arm (RSP 9651, Cavro ScientificInstruments, Inc., Sunnyvale, Calif.) mounted on a platform was fittedwith a fluoropolymer-coated steel needle probe (Cavro part #722470), a500 μL piston syringe pump (Cavro, model XL 3000) connected to theneedle probe by flexible fluoropolymer tubing, and a fluoropolymer probewash/waste station was mounted on the platform. Features of the RSP-9651include capacitance based liquid-level sensing, optical step loss motiondetection and completely programmable motor speeds and accelerationprofiles. A serial interface, electrically actuated 8-port valve (modelEHC8W, Valco Instruments Co. Inc.) was mounted to the platform,controlled by the same computer as the sampler. The valve was mountedwith two 50 μL sample loops, a waste line, and a port comprising afluoropolymer liner in a steel nut (Valco, VISF-1), sized to fit a 22gauge needle (0.028 in. O.D.) for manual loading of samples with asyringe. The inner diameter of the steel nut was milled larger (from0.0645 in. to 0.076 in.), and the outermost 0.25 in of the fluoropolymerliner was enlarged within the nut to an inner diameter of ca. 0.042 in,to accommodate the coated sampler probe needle, which has an outerdiameter of 0.0425 in. With the probe needle inserted 0.20 in into theport, it was found that the mating fluoropolymer surfaces prevented anyleaking of fluid as the sample introduced fluid into the port, even atflow rates exceeding 60 mL/min. In this configuration, it was stillpossible to manually load individual samples into the loops on the valvewithout leaking, using a hand-held syringe with a 22-gauge needleinserted fully into the same port.

[0298] The valve was also fitted with inlet and outlet flow linesleading to an HPLC system. The flow was provided by two pumps (Waters,model 515) capable of generating a solvent gradient, and thechromatography system was provided with fittings for inserting columns,filters, and detection systems including a light scattering detector(Precision Detectors, model PD 2020) enclosed within the housing of arefractive index detector (Waters, model 410). The systems also had a UVdetector (Waters, model 486). The light-scattering detectorsimultaneously measured the static light scattering signals at 15 and 90degrees, and the dynamic light scattering signal at 90 degrees. Aninterface box (264 in FIG. 2) acquires signals from all detectors.

[0299] A 96-well microtiter plate filled with water was placed on theplatform, the syringe pump and probe were primed with water, and thecomputer was programmed with the locations and of the plate, the washand waste stations, and the valve port. The instrument was programmed,and the following sequence of operations were executed: (1) drawing a100 μL sample from position 1 of the microtiter plate; (2) loading the50 μL sample loop with 80 μL of the drawn sample; (3) actuating thevalve to inject the sample into the flow system; (4) expelling theremaining sample to waste and rinsing the inlet port of the valve with200 μL of fresh diluent; (5) moving the probe to the cleaning stationand cleaning with an additional 200 mL of diluent in preparation for thenext sample; and (6) repeating steps (1) through (5) with each samplesfrom positions 2-96 of the microtiter plate.

[0300] All of these operations were performed with an averagesample-throughput of less than 8 seconds per sample. Such rapid-samplingrate is well suited to the rapid characterization methods of thisinvention.

Example 2 Auto-sampler with Two Robotic Arms

[0301] This example demonstrates rapid, automated (robotic) preparationand sampling of combinatorial libraries using two robotic arms, allowingfor multiple, simultaneous analyses.

[0302] A robotic sampler was prepared in a similar manner to Example 1,except using a two-arm XYZ robot (Cavro, model RSP 9652), two injectionvalves (Valco, model EHC8W), and four pumps (Cavro, model XL 3000). Foreach arm, two pumps were connected in series to a single probe needle onthe arm, one pump fitted with a 500 μL syringe, and one pump with a 5000μL syringe. In this configuration, good flow precision was obtained withthe smaller volume pump when needed, while the larger volume pump candeliver instantaneous flow rates of approximately 300 mL/min and overallflow rates greater than 100 mL/min, allowing for very rapid rinsing,washing, and sample manipulation.

[0303] Liquid samples from an array of vessels were rapidly loaded andinjected using this system, with intermittent steps including washingand rinsing, in a manner similar to that described in Example 1. Theseoperations were performed with an average sample-throughput of about 4seconds per sample.

Example 3 Precipitation—Redissolution Chromatography

[0304] This example demonstrates the use of a liquid chromatographysystem for rapid chromatographic separation of polystyrene polymerstandards using precipitation-redissolution chromatography with amobile-phase composition gradient. The results provided a calibrationfor the chromatographic system and conditions.

[0305] The robotic auto-sampler and injection valve set-up as in Example1 was fitted with two sample loops (each having 50 microliter volume) incombination with a high-pressure liquid chromatographic (HPLC) apparatuscomprising a two-pump gradient chromatography system, primed withmethanol and tetrahydrofuran (THF) solvent. A porous crosslinkedpolystyrene monolithic column was utilized, prepared as described inFrechet et al., Journal of Chromatography A, 752 (1996) 59-66 andFréchet et al., Anal. Chem. 1996, 68, 315-321. The HPLC system wasconfigured such that the combined flow of the pump system passed throughthe valve, the column, and then to a UV chromatographic detector. Theentire system, including pump control and data acquisition from thedetector was computer-controlled.

[0306] Filtered solutions in THF of 12 commercially available (AldrichChemical Co. Inc.) narrow molecular weight distribution polystyrenestandards of various molecular weights were dissolved in THF at anominal concentration of 5.0 mg/mL. Nominal molecular weights rangedfrom 760 g/mol to 1,880,000 g/mol. Each of these polymer samples wereserially injected into the mobile phase of the liquid chromatographysystem while varying a range of chromatographic parameters, includingtotal pump flow and gradient composition and speed, to obtain reasonableseparation of the various standards in a short time.

[0307] In one experiment, the following conditions were chosen: TABLE 1Mobile-Phase Conditions Time (min) Parameter Value 0.0 Total flow 10mL/min. 0.0 Starting Solvent Composition 30% THF: 70% Methanol 0.35Begin Linear Gradient To 70% THF: 30% Methanol 1.20 End Gradientmaintain at 70% THF: 30% Methanol 1.50 Begin Linear Gradient to initialsolvent composition 1.60 Initial Solvent Composition Reestablished (30%THF: 70% Methanol)

[0308] The resulting chromatographic traces showed a linear increase inUV absorbance during the gradient due to the linear change in solventcomposition. The profile of this gradient, measured with no sampleinjected, can be subtracted from each chromatogram to simplify theappearance of the raw data obtained for each sample. Using thechromatographic conditions described above, the following peak retentiontimes for the standards were measured: TABLE 2 Peak Retention Times forPolystyrene Standards Nominal Molecular Weight Retention Time (min) 760Not observed 3700 Not observed 13700 0.7987 18700 0.8785 29300 0.932344000 0.9794 114200 1.0440 212400 1.0849 382100 1.1195 679000 1.1430935000 1.1458 1880000 1.1650

[0309] The results of Table 2 comprise a calibration of the column andchromatographic conditions—thereby allowing subsequent determination ofpeak molecular weight or molecular weight distribution for samples ofunknown molecular weight.

Example 4 Rapid Flow-injection Light Scattering

[0310] This example demonstrates a rapid flow-injection light-scattering(FILS) technique in which light-scattering measurement techniques wereused to determine an average molecular weight of a polymer samplewithout chromatographic separation of the sample.

[0311] The general layout of the system was generally as described inExample 1, and as shown in FIG. 7, including an eight-port injectionvalve 210 (See FIG. 3), a filter 212, and no column 214. A lightscattering detector 216 and a RI detector 218 were used. Samples wereinjected with a syringe, by hand, into the 8-port injection valve, thevalve having two 50-μl injection valves. The system was maintained at atemperature of 36° C.

[0312] M_(w) for each sample was calculated using an algorithmincorporated in the analysis software (“Precision Analyze”, version0.99.031(06/08/97), Precision Detectors) accompanying the PD2020. Inorder to determine M_(w), points in the chromatogram representing thebaselines of the 15 and 90 degree signals and the RI signals were firstselected (“baseline regions”). Linear least-squares fits of these pointsdefined the three baselines. Then, an integration region encompassingthe main sample peak was chosen. The software then calculated M_(w)based on the SLS and RI data and baseline values in this integrationregion. The calculation was performed in the limit of the radius ofgyration, R_(g), being much less than the measurement wavelength, andthe polymer concentration in the dilute limit representing isolatedmolecules. This calculation also used the angular form-factor, P(θ),appropriate for a Gaussian-coil molecule, and fitted it to the SLSsignals to extract M_(w). For polymers with M_(w) less than about 10,000kD, this method determined values of M_(w) within less than 5% of valuescalculated assuming non-Gaussian-coil forms of P(θ).

[0313] R_(h) was calculated from the diffusion constant of the polymermolecules, which is obtained by fitting the photon-photon correlationfunction to an exponential. The PD2020 system was designed to allow formeasurements of R_(h) at each time-slice of the chromatogram forsufficiently low flow rates.

[0314] A series of polystyrene Mw-standards in THF as described inExample 3 were measured using the system just described. The solventflow rate was 0.5 ml/min, and the injection volume was 50 μl. The widthof the signal peaks in the flow-injection analysis output data weretypically 0.3 min. The centers of the SLS peaks appeared at about 0.35min after each injection. For comparison, the same series of standardswas run with the same system altered to include a set of conventionalGPC columns (Polymer Laboratories, 1110-6500) placed between the filterand the light-scattering cell.

[0315] Table 3 shows the experimental M_(w) values for each of thestandards, determined with a liquid chromatography system with thecontrol conventional GPC columns in place, and with the flow-injectionanalysis method disclosed herein. The Mw values measured followed theexpected overall trend except for the 13.7 kD and 0.760 kD samples.There was fairly close quantitative agreement between measured andnominal values over most of the range of molecular weights. Note thatthere was very good quantitative agreement between the values measuredwith the conventional GPC columns and the nominal values. TABLE 3 RapidFlow-Injection Analysis versus Conventional GPC Measured M_(w) (kD)Rapid Light Scattering (conventional GPC. Method measured M_(w) NominalM_(w) (kD) Columns) (kD) 0.76 0.72 35 2.36 2.04 17 3.70 3.88 21 13.712.3 56 18.7 18.6 53 29.3 25.3 63 44.0 44.2 80 114 106 134 212 220 171382 385 240 679 704 285 935 954 421 1880 1709 1760

[0316] The following Table 4 shows a comparison of the R_(h) values ofthe same samples using (1) conventional GPC chromatography, (2) the RFLSmethod of this Example and (3) the literature values of the samples.There was good quantitative agreement across all three sets of valuesfor the 44 kD through 935 kD samples. For samples with weights 29.3 kDand below, reliable measured values were not acquired. Literature valuesof R_(h) were derived from a fit to data published in: W. Mandema and H.Zeldenrust, Polymer, vol. 18, p.835, (1977). (In Table 4, NA=notavailable) TABLE 4 Comparison of Nominal and Measured R_(h) ofPolystyrene Standards Nominal Literature R_(h) (nm) measured R_(h) (nm)measured R_(h) (nm) M_(w) (kD) (T = 24 deg C.) (conven. columns) (nocolumns) 0.76 NA NA NA 2.36 NA NA NA 3.70 NA NA NA 13.7 NA NA NA 18.73.8 NA NA 29.3 4.9 NA NA 44.0 6.1 6.5 9 114 10 8.8 12 212 15 13 15 38221 17 20 679 29 23 25 935 34 27 30 1880 51 37 35

[0317] These data demonstrate that rapid, meaningful measurements ofmolecular weight are available by the methods of the invention, with nochromatographic separation of polymeric components. In this example, theaverage sample-throughput (i.e., measurement time) was about 0.3min/sample (about 20 seconds per sample).

[0318] As disclosed herein, other variations can be effected to achieveeven faster measurements, for example, by controlling flow rate, samplesize, acquisition times and other parameters. It is also possible tomeasure the radius of gyration, R_(g), using this experimental set-up bycomparing the relative amplitudes of the 15 and 90 degree SLS signals.The system should preferably be calibrated with high precision using alow-M_(w) polymer standard in order to measure R_(g) successfully, asthe angular anisotropy of the scattering is weak.

Example 5 Rapid Size Exclusion Chromatography

[0319] This example demonstrates a rapid liquid-chromatographylight-scattering measurement using the short, high-aspect ratio columnusing the same 12 commercially available polystyrene standards as usedin Example 4.

[0320] The set-up was the same as in Example 4, with the exception ofthe presence of a short chromatographic column (Polymer Laboratories,1110-1520, sold as a GPC “guard column”) inserted in-line between thefilter and the light-scattering cell. Briefly, the column was 7.5 mm indiameter and 5 cm height and was packed with polystyrene beads targetedto pass sample components having a molecular weight greater than about1000 without substantial separation thereof.

[0321] M_(w) was calculated using the algorithm in Precision Analyze,version 0.99.031 (Jun. 8, 1997), in the same way as in Example 4 over anintegration region (including elution times between 0.2 and 0.36minutes). The software allowed for automatic analysis of a series offiles without requiring the operator to manually choose integration andbaseline regions for each file individually.

[0322] A set of polystyrene standards in THF were prepared and measuredas described in Example 4. In addition, mixtures of polystyrene withvarying amounts of styrene monomer and polymerization catalyst (oxidizedform of CuCl with 2 equivalents of 4,4′-bis(5-nonyl)2-2′-bipyridine)were also measured. The flow rate was set to 4 ml/min in all cases.

[0323] In the case of pure polystyrene in THF, Table 5 below shows thatthe measured molecular weights agree the nominal weights, with generallybetter agreement than in Example 4. In the case of the highest M_(w),the integration region partially encompassed an extraneous peak in theDRI signal at 0.34 min, possible due to contamination. Manually settingthe integration region in this case to exclude the extraneous peakyields a more accurate (1740 kD) value. In all cases, the characteristicpeak in the RI signal due to the carrier solvent eluted at times laterthan the polymers. Consequently, the solvent peak could be excluded fromthe M_(w) calculation, thereby improving the accuracy of the weightdetermination. TABLE 5 Nominal and Measured M_(w) of Pure PolystyreneStandards Nominal M_(w) (kD) Measured M_(w) (kD) 0.760 2.5 2.36 5.0 3.703.7 13.7 14 18.7 18 29.3 27 44.0 43 114 100 212 200 382 300 679 560 935710 1880 860

[0324] For solutions containing polystyrene and styrene monomer, Table 6confirms that the measured molecular weights are independent of themonomer concentration, because the polymer (elution times rangingbetween 0.23 and 0.31 min) eluted separately from the monomers and othersmall molecule components of the sample, which elute at about 0.39 min.TABLE 6 Nominal and Measured Mw of Polystyrene Standards with VaryingStyrene (Monomer)-to-Polystyrene Ratios styrene/polystyrene MeasuredM_(w) (kD) Nominal M_(w) (kD) (weight ratio) (short column) 2.36 0.5 6.52.36 1 2.5 2.36 2 1.7 2.36 4 1.6 2.36 8 2.0 29.3 0.5 26 29.3 1 26 29.3 226 29.3 4 25 29.3 8 25 679 0.5 560 679 1 580 679 2 600 679 4 590 679 8580

[0325] The chromatograms of the polystyrene-catalyst mixtures do notshow clear peaks attributable to the catalyst molecules. Furthermore,the heights and shapes of the polymer SLS and DRI traces do not changeappreciably with the concentration of catalyst. Table 7, below, showsthat the measured molecular weights are independent of the catalystconcentration. TABLE 7 Nominal and Measured Mw of Polystyrene Standardswith Varying Amounts of Catalyst measured M_(w) (kD) Nominal M_(w) (kD)catalyst weight % (short column) 2.36 0.5 4.0 2.36 1 4.7 2.36 5 5.7 29.30.5 25 29.3 1 28 29.3 5 28 679 0.5 580 679 1 570 679 5 570

[0326] Thus, these data demonstrate rapid characterization of polymersamples and good correlation between the measured and nominal molecularweights of polystyrene standards, with and without added monomer andcatalyst components, using a short, high-aspect ratio chromatographiccolumn. The sample-throughput for the plurality of samples was about 18seconds per sample.

Example 6 Flow-injection Light-scattering w/Emulsion Polymer Samples

[0327] This example demonstrates flow-injection light-scattering (FILS)using a dynamic light-scattering detector (DLS) to determine particlesize (R_(h)) for an array of emulsion polymers.

[0328] An array of emulsion polymers was prepared as in Example 10,below, with the following change. Solution No. 8 was replaced with waterin rows 7 and 8. Diluted samples of these emulsions were prepared inwater by serial dilution in three stages to 1/30,000 of the library assynthesized. Using the auto-sampler described in Example 1, with a flowrate of 0.3 mL/min. of water, a sample volume of 50 μL and an in-line 2μm filter, the sample was introduced directly into the DLSdetector—without any chromatographic separation column. Samples wereinjected at 2 min. intervals. The instrument was calibrated with knownpolystyrene particle size standards (Duke Scientific, Palo Alto, Calif.,nominal R_(h) of 9.5 nm, 25 nm, 51 nm and 102 nm).

[0329] As each sample moved through the detector, between 15 and 50independent measurements of R_(h) were obtained. Statistically invalidmeasurements were removed and the remaining results were averaged. TheseR_(h) values (in nm) are shown below in Table 8. TABLE 8 HydrodynamicRadius Determined by Flow-Injection Light-Scattering Row/ Col 1 2 3 4 56 7 8 9 10 11 12 1 45.2 42.4 39.7 76.0 N.D. N.D. 43.6 52.3 N.D. 68.484.5 N.D. 2 40.4 N.D. 36.8 N.D. N.D. N.D. 39.2 39.5 58.3 56.6 63.7 99.63 45.2 44.8 42.0 48.1 75.8 N.D. 47.9 51.1 51.7 49.0 69.9 87.9 4 41.537.9 38.5 69.8 39.4 86.9 41.8 42.5 48.1 47.8 57.2 80.8 5 42.2 39.6 38.637.4 41.0 44.4 45.6 58.2 71.5 46.4 60.0 73.9 6 N.D. 38.4 36.2 40.0 36.637.8 41.5 42.1 49.4 42.7 49.9 62.4 7 N.D. N.D. N.D. N.D. N.D. N.D. N.D.N.D. N.D. N.D. N.D. N.D. 8 N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D. N.D.N.D. N.D. N.D.

[0330] These data show that the flow-injection light-scattering methodsof this invention usefully screen emulsion samples for variation inparticle size. Rows 7 and 8, which contained water and no surfactant,produced unstable emulsions, as predictable, and no meaningful DLScorrelation was obtained, as was predicted.

Example 7 High-temperatufe Characterization with RapidLiquid-chromatography

[0331] This example demonstrates rapid liquid-chromatography with ashort, high-aspect ratio column and light-scattering detectors todetermine the molecular weight of polymers soluble at high-temperatures.

[0332] The experimental apparatus for this example was as shown in FIGS.7A and 7B and discussed in connection therewith, except for thefollowing deviations: (1) the auto-sampler probe 201 was equipped with athermostatically controlled heating element to form a heated probe(tip); (2) the sample container 202 was likewise equipped with athermostatically controlled heating element; and (3) the loading port204 and external portions of the transfer line 206 were also heated witha thermostatically controlled heating element. The remaining componentsof the system were in a temperature-controlled oven (high-temperatureGPC (Polymer Laboratories model 210)). The temperature of the oven wasmaintained at about 140° C. (but the oven could vary in temperature from35° C. to 210° C.). The injection valve was a six-port valve with thesample loop of the injection valve having volume of about 20-μl. Afilter was employed. The mobile-phase flow rate was about 4 ml/min.

[0333] The polymer samples were injected into the system at intervals ofabout 60 seconds, filtered in-line and then chromatographicallyseparated with a short, high-aspect ratio column packed with traditionalhigh temperature GPC packing material (Polymer Laboratories, 1110-1520).The separated sample was detected with a static light scatteringdetector (Precision Detectors light-scattering system (PD2040)) and a RIdetector (supplied from Polymer Laboratories with the oven) configuredin series in that order. Two computers were used to controlled thesystem substantially as described in connection with FIG. 7B.

[0334] M_(w) was calculated using the algorithm in Precision Analyze,version 0.99.031 (Jun. 8, 1997), in the same way as in Experiment 4.

[0335] Commercially available polyethylene samples and a broad MWDsample available from Aldrich were evaluated in this system. Table 9shows the results: TABLE 9 Nominal and Measured M_(w) Sample nominalM_(w) (kD) Measured M_(w) (kD) Polyethylene-broad 35 24 distributionPolyethylene standard 76.5 140 Polystyrene standard 68.6 74 Polystyrenestandard 212.7 140

[0336] These results show the method is particularly useful fordifferentiating between polymers having approximately a factor of 2difference in average molecular weight. Thus for libraries of polymershaving molecular weights on the order of 10³ versus polymers havingmolecular weights on the order of 10⁴ versus polymers having molecularweights on the order of 1 are easily distinguished. As can be seen, veryrapid measurement (average sample-throughput of about 1 minute) ofweight average molecular weight is possible at high temperature. Theelution times of these samples were all about 0.25 min, with peak widthsof 0.08 min. The solvent elutes at 0.46 min, with a width of 0.13 min.This system can also be operated faster than in this example, asdiscussed above.

Example 8 Characterization of a Combinatorial Polymer Library with RapidLC

[0337] This example demonstrates the synthesis and rapidcharacterization of a combinatorial library of polystyrene polymers withrapid liquid chromatography.

[0338] In a dry, nitrogen atmosphere glovebox two stock solutions (I andII) were prepared. Ligand L-1 having the structure shown below was usedin stock solutions I and II:

[0339] L-1 was synthesized from reductive coupling of4-(5-nonyl)pyridine using Pd/C catalyst at 200° C. L-2 was purchased.

[0340] 1-chloro-1-phenylethane (hereinafter “I-1”) was synthesized bytreatment of styrene with HCl and purified by distillation. 1-2 wassynthesized by reaction of commerially available divinylbenzene withHCl, followed by purification by distillation. I-2 had the followingstructure:

[0341] All other materials were commercially available and were purifiedusing conventional techniques.

[0342] Solution I comprised 20.8 mg (0.21 mmol) of CuCl, 179.5 mg (0.44mmol) of compound L-1, 10.9 g (0.105 mol) of styrene and 37.1 mg (0.21mmol) of I-1. Solution II comprised 20.8 mg (0.21 mmol) of CuCl, 179.5mg (0.44 mmol) of compound L-1, 10.9 g (0. 105 mol) of styrene and 38.3mg (0. 105 mmol) of I-2. A 10-row by 11-column 110-vessel glass-linedaluminum reactor block array with approximately 800 uL volume pervessel, was prepared in a drybox under dry nitrogen atmosphere, andstock solutions I and II manually distributed to the vessels using ametering pipettor, such that elements 1-55 (5 rows by 11 columns)received 200 μL of solution I and elements 56-110 (also 5 rows by 11columns) received 200 μL of solution II. To this array was addedadditional solvent such that each row of the two 5×11 arrays received adifferent solvent, with each column received a different amount of thesolvent. The five solvents used were benzene (rows 1,6),o-dichlorobenzene (rows 2,7), m-dimethoxybenzene(rows 3,8), diphenylether (rows 4,9), and diethyl carbonate (rows 5,10). The 11 columnsreceived a gradient of dilutions in even increments from 0 to 400 uL insteps of 40 uL. In this fashion an array of 10×11 diverse polymerizationreactions were prepared, requiring a setup time of approximately 3.5hrs.

[0343] The reactor block array was sealed, removed from the glovebox,and heated to 120° C. for 15 hrs with agitation provided by an orbitalshaker. The reactor block was allowed to cool, and to each vessel wasadded 0.5 mL of tetrahydrofuran solvent, and the block was sealed andheaded at 105° C. with orbital shaking for approximately 1 hour, to;allow formation of uniform, fluid solutions, and the reactor block wasallowed to cool.

[0344] Each element of the array was analyzed by rapid, automated liquidchromatography using a system substantially the same as shown in FIG. 7Aand described in connection therewith and in a manner similar to thatdescribed in Example 3. Using the automated sampler, samples of eachvial, ranging from 6 to 16 μL were drawn (5+column number=volume in μL,sampling more volume from higher numbered columns in order to have moreequal amounts of polymer, in anticipation of lower monomer conversionwith increasing dilution). Each sample was dispensed into a wellcontaining approximately 2 mL of methanol, in a polypropylene deep-wellmicrotiter plate, precipitating any solid polymeric product.

[0345] For each well, the methanol was robotically decanted and thesolid polymeric product washed with 1 mL additional methanol. The solidpolymeric product was redissolved with robotic mixing in 0.5 mLtetrahydrofuran, and a 100 μL sample of this solution was drawn and usedto load a 50 μL sample loop, followed by rapid chromatographicevaluation. During the time of each chromatographic run, the steps ofwashing and redissolving the next sample were conducted, so that eachsample injection automatically occurred at 110 sec intervals. Table 10,below, shows the peak molecular weight/1000 of the samples derived fromthe analysis. Where little or no polymer was detected in the analysis, azero is indicated. In most cases this is due to samples with lowmolecular weight, where the polymeric product precipitated into methanolas a fine slurry that was removed during the washing step and notretained for redissolution and analysis. TABLE 10 Peak MolecularWeight/1000 Col 1 2 3 4 5 6 7 8 9 10 11 Row 1 48.9 46.8 44.1 0.0 0.0 0.00.0 0.0 0.0 0.0 0.0 2 48.8 44.1 0.0 40.7 40.7 40.0 0.0 0.0 31.1 0.0 0.03 49.9 44.1 40.7 40.7 40.7 45.0 42.4 40.0 0.0 0.0 0.0 4 49.9 44.1 44.136.4 38.5 0.0 0.0 0.0 0.0 0.0 0.0 5 49.9 40.0 33.9 31.1 0.0 0.0 0.0 0.00.0 0.0 0.0 6 74.3 62.4 55.6 48.8 46.8 40.0 36.4 33.3 0.0 0.0 0.0 7 65.561.0 61.0 55.6 55.6 52.1 49.9 48.8 46.8 42.4 40.7 8 0.0 62.4 58.2 55.658.2 37.1 54.4 49.9 52.1 48.8 48.8 9 68.8 58.2 55.6 58.2 54.4 52.1 65.549.9 48.8 45.0 40.7 10 65.5 49.9 44.1 38.5 33.3 22.8 0.0 20.4 0.0 0.00.0

[0346] Each element of the array was analyzed by a second time, with thefollowing changes in attempt to obtain more rapid analysis: samples ofeach vial, ranging from 10 to 60 μL were drawn (5+5×column number=volumein μL). Each sample was dispensed with agitation into a well containingapproximately 2 mL of methanol, in a polypropylene deep-well microtiterplate, precipitating any solid polymeric product. For each well, themethanol was robotically decanted. With no further washing, the solidpolymeric product was redissolved with robotic mixing in 0.5 mLtetrahydrofuran, and analyzed as above. Table 11, below, shows the peakmolecular weight of the samples derived from this second analysis. In afew cases, polymer was detected where none was seen in the previousanalysis, and the chromatographic data was more complicated due to thepresence of more low-molecular weight impurities, but in general, thesame molecular weight trends were observed. TABLE 11 Peak MolecularWeight/1000 Col 1 2 3 4 5 6 7 8 9 10 11 Row 1 49.2 49.2 46.2 0.0 0.0 0.00.0 0.0 0.0 0.0 0.0 2 49.2 46.2 41.8 42.6 44.3 41.8 0.0 0.0 30.6 0.0 0.03 49.2 47.2 44.3 41.8 44.3 51.4 46.2 49.2 0.0 0.0 0.0 4 47.2 46.2 51.435.2 40.2 49.2 49.2 0.0 0.0 0.0 0.0 5 47.2 42.6 33.4 31.7 21.5 0.0 0.00.0 0.0 0.0 0.0 6 64.8 61.7 61.7 51.4 47.2 40.2 36.5 33.4 0.0 0.0 0.0 761.7 61.7 61.7 57.5 57.5 54.9 49.2 51.4 49.2 46.2 41.8 8 46.2 64.8 61.757.5 61.7 40.2 54.9 57.5 57.5 51.4 51.4 9 64.8 64.8 58.8 57.5 58.8 58.866.4 66.4 47.2 49.2 42.6 10 61.7 54.9 44.3 41.8 33.4 23.4 17.8 20.9 0.00.0 0.0

[0347] Each element of the array was analyzed by a third time, with thefollowing changes relative to the first analysis, to more slowly andthoroughly purify the polymeric product before analysis. Samples of eachvial, ranging from 10 to 60 μL were drawn (5+5×column number=volume inμL). Each sample was dispensed with agitation into a well containingapproximately 2 mL of methanol, in a polypropylene deep-well microtiterplate, precipitating any solid polymeric product. For each well, themethanol was robotically decanted. To each well was added 1.0 mL ofadditional methanol with agitation. This procedure was completed for all110 wells before any chromatographic analysis was begun, to allow moretime for extraction of low-molecular weight impurities and moreefficient settling of the solid polymeric product. Then for each well,the methanol was decanted, the solid polymeric product was redissolvedwith robotic mixing in 0.5 mL tetrahydrofuran, and the polymer wasanalyzed as above. Table 12, below, shows the peak molecular weight ofthe samples derived from this third analysis. In general, the samemolecular weight trends were observed. TABLE 12 Peak MolecularWeight/1000 Col 1 2 3 4 5 6 7 8 9 10 11 Row 1 53.7 49.1 51.3 0.0 0.0 0.00.0 0.0 0.0 0.0 0.0 2 51.3 49.1 0.0 46.0 46.0 46.0 0.0 0.0 30.2 0.0 0.03 48.0 51.3 49.1 44.1 46.0 51.3 49.1 43.2 0.0 0.0 0.0 4 48.0 48.0 51.337.6 41.5 41.5 0.0 0.0 0.0 0.0 0.0 5 48.0 48.0 35.5 32.4 23.7 0.0 0.00.0 0.0 0.0 0.0 6 0.0 74.3 68.6 57.6 57.6 44.1 39.9 35.5 0.0 0.0 0.0 770.4 74.3 62.0 65.2 65.2 62.0 57.6 55.0 57.6 49.1 48.0 8 49.1 70.4 65.265.2 70.4 70.4 65.2 60.5 62.0 57.6 55.0 9 70.4 70.4 68.6 68.6 74.3 74.385.5 62.0 60.5 46.0 39.9 10 78.5 57.6 48.0 39.1 31.3 17.6 0.0 0.0 0.00.0 0.0

Example 9 Characterization of a Combinatorial Polymer Library with RapidLC

[0348] This example demonstrates characterization of a combinatorialpolymer library with rapid liquid chromatography using short,high-aspect ratio columns in combination with light-scatteringdetection. The method of screening of Example 5 was used with acombinatorial library of controlled radical polymerizations.

[0349] Materials I-1, I-2, and L-1 were prepared as in Example 8. Allother materials were commercially available and were purified usingconventional techniques.

[0350] Five stock solutions were prepared in a dry nitrogen atmosphereglovebox (I, II, III, IV, and V), as follows: Solution I comprised 19.8mg (0.141 mmol) of 1-chloro-1-phenylethane (I-1) and 800 μL (6.98 mmol)of styrene. Solution II comprised 20 mg (0.2 mmol) CuCl, 174 mg of L-1(0.42 mmol), and 3.33 mL (29.1 mmol) of styrene. Solution III comprised14.2 mg of I-2 (0.07 mmol) and 800 μL (6.98 mmol) styrene. Solution IVcomprised 14.7 mg (0.105 mmol) of I-1, 10.4 mg (0.105 mmol) CuCl, 90 mg(0.022 mmol) of L-1, and 6 mL (52.4 mmol) of styrene. Solution Vcomprised 10.7 mg (0.0525 mmol) of 1-2, 10.4 mg (0.105 mmol) CuCl, 90 mg(0.022 mmol) of L-1, and 6 mL (52.4 mmol) of styrene.

[0351] A 7-row by 12-column 84-vessel glass-lined aluminum reactor blockarray with approximately 800 μL volume per vessel, was prepared in adrybox under dry nitrogen atmosphere, and stock solutions I-V weremanually distributed to the vessels using a metering pipettor, such thatelements 1-5 received a gradient of Solution I (100 μL, 50 LL, 33.3 μL,25 μL, and 20 μL), 100 μL of Solution II, and a gradient of excessstyrene (0 μL, 50 μL, 66.7 μL, 75 μL, 80 μL). Elements 6-10 received agradient of Solution III (100 μL, 50 μL, 33.3 μL, 25 μL, and 20 μL), 100μL of Solution II, and a gradient of excess styrene (0 μL, 50 μL, 66.7μL, 75 μL, 80 μL). Elements 11-15 received a gradient of Solution I (100μL, 50 μL, 33.3 μL, 25 μL, and 20 μL), 100 μL of Solution II, a gradientof excess styrene (0 μL, 50 μL, 66.7 μL, 75 μL, 80 μL), and 200 μL ofdiphenylether. Elements 16-20 received a gradient of Solution 11 (100μL, 50 μL, 33.3 μL, 25 μL, and 20 μL), 100 μL of Solution 11, a gradientof excess styrene (0 μL, 50 μL, 66.7 μL, 75 μL, 80 μL), and 200 μL ofdiphenylether. Elements 21-50 (a 5×6 array) received 150 μL of SolutionIV and a gradient of dilutions along each row by adding solvent (75 μL,150 μL, 225 μL, 300 μL, 375 μL, 450 μL) with a different solvent in eachrow (diethyl carbonate, benzene, o-dichlorobenzene, m-dimethoxybenzene,and diphenylether, respectively). Similarly, elements 51-80 (a 5×6array) received 150 μL of Solution V and a gradient of dilutions alongeach row by adding solvent (75 μL, 150 μL, 225 μL, 300 μL, 375 μL, 450μL) with a different solvent in each row (diethyl carbonate, benzene,o-dichlorobenzene, m-dimethoxybenzene, and diphenylether, respectively).In this fashion an array of 7×12 diverse polymerization reactions wereprepared, requiring a setup time of approximately 5 hrs. The reactorblock array was sealed using a Teflon membrane covering a silicon rubbersheet compressed with an aluminum plate bolted in place.

[0352] The array was then heated to 120° C. for 15 hrs with agitationprovided by an orbital shaker. The reaction block was allowed to cool,and to each vessel was added THF such that the total volume reached 0.8mL, and the block was sealed and heated at 105° C. with orbital shakingfor approximately 1 hr, to allow formation of homogeneous fluidsolutions. The reactor block was allowed to cool.

[0353] Each element of the array was analyzed by rapid manner asdescribed in Example 5, with the following procedure. Using aprogrammable robotic sampler, 20 μL of each vial were drawn anddispensed along with 250 μL of THF into a polypropylene microtiterplate. 100 μL of this diluted sample was drawn and used to load a 50 μLsample loop on an HPLC injector, followed by rapid LS evaluation. Duringthe time of each analysis, the step of diluting the next sample wasconducted, so that each sample injection automatically occurred at 40sec. intervals. Table 13, below, shows the average M_(w)/1000 of thesamples derived from the analysis. TABLE 13 Average M_(w)/1000 Col 1 2 34 5 6 7 8 9 10 11 12 Row 1 22.2 35.7 46.3 55.8 63.7 NR NR 25.9 47.6 57.372 78.2 2  8.65 15 22.3 26.6 30.4 NR NR 11.2 19.8 33.1 40.1 42.9 3 28.920.2 16.6 12.6 12 11.9 44 34.3 29.8 20.9 17.6 16.4 4 38.9 29.6 26.1 24.124.2 22.9 56 51.7 45 38.7 30.9 27 5 47.8 34.8 23.6 18.6 15.4 14.1 59.948.3 33.7 25.2 22.6 18.3 6 40.6 28.6 15.3 12.9 12 13.1 45.8 20.8 17.712.3 13.3 13.8 7 40.3 30.2 23.2 20.9 19.5 19.2 46.8 37.4 34.2 29.7 28.627.8

[0354] The expected trends of decreasing molecular weight withincreasing dilution were observed. This demonstrates very rapidmolecular weight determinations in combinatorial discovery of optimalcatalytic processes.

Example 10 Characterization of Emulsion Samples with RapidSEC—Adsorption LC

[0355] This example demonstrates rapid size exclusion chromatography(SEC), combined with adsorption chromatography for determining molecularweight, MWD and residual monomer concentration (i.e., conversion) in thepresence of water in a combinatorial library of emulsion polymers. Morespecifically, the GPC characterization of hydrophobic polymers andconversion analysis in a single run is demonstrated. In such cases, themonomer peak can often be overlapped with a peak of the solvent used forpolymerization; however, the approaches disclosed herein overcome thispotential pitfall.

[0356] This specific example describes a method for both molecularweight characterization of polymer as well as quantitative analysis ofmonomer and polymer in a sample prepared by emulsion polymerization. Thetechnique is based on combination of size-exclusion and adsorptioneffects. A size separation of polymer and monomer is obtained whilewater is adsorbed under these conditions and not interfering with theanalysis.

[0357] The system used is described in Example 3, using an eight portValco injection valve, a Waters 515 pump, a Waters UV-VIS 486 detector,a LS detector PD 2000 built inside the RI unit. (Also, a Waters 410 RIdetector was connected to the system, but not used for this particularexample. It was used in a later, related example.) A series of two 50×8mm hydrophilic columns Suprema 30 Å and 1000 Å from Polymer StandardServices were used for the analyses. (A later experiment that followedthis example combined the two columns together in a single mixed bedcolumn, which provided equivalent, but slightly better separation). Thechromatography was performed using THF as the mobile phase at variousflow rates (1, 2, 5, and 10 mL/min). The chromatographic separation wascompleted in less than 2 min per sample (at 2 mL/min) with goodresolution of separation and precision of the molecular weightdetermination at these flow rates. The separation can be obtained inabout 20 seconds (at 10 mL/min), with some impact on the precision ofthe method.

[0358] An 8-row by 12-column combinatorial library array of 96 emulsionpolymerization reactions was prepared according to the followingprocedure. Nine 20 ml vials were prepared with neat monomer, 10%surfactant solutions or initiator solution as described below, all fromcommercially available materials without further purification. Solutionvials were as follows: Solution Vial Contents 1) styrene 2) butylacrylate 3) methyl methacrylate 4) vinyl acetate 5) sodium dodecylsulfate (SDS)(Aldrich, 10 wt % in water) 6) sodiumdodecylbenzenesulfonate (SDBS)(Aldrich, 10 wt % in water) 7) RhodacalA246L (A246L)(Rhone Poulenc, diluted to 10 wt % in water) 8) Dowfax 2A1(2A1)(Dow Chemical Co., diluted to 10 wt % in water) 9) K2S208 (4 wt %in water)

[0359] A 96-member array of glass vessels in an aluminum reaction blockwas prepared. In an oxygen-free glovebox, using an automated sampler asdescribed in Example 1, three of the above 9 solutions were dispensed toeach vessel in the array, as shown in the following Table 14. Water wasadded to each vessel to bring the total volume to 500 μL. Solution 9 wasadded last to all of the vessels. The total time required for theautomated, robotic dispensing was approximately 18 minutes. Each elementof the table contains the solution number-quantity of that solution, inmicroliters. TABLE 14 Sample-Preparation Row Col 1 2 3 4 5 6 7 8 9 10 1112 1 1-125 1-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-125 4-1504-175 5-6.3 5-7.5 5-8.8 5-6.3 5-7.5 5-8.8 5-6.3 5-7.5 5-8.8 5-6.3 5-7.55-8.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 2 1-125 1-150 1-175 2-125 2-150 2-175 3-125 3-1503-175 4-125 4-150 4-175 5-12.5 5-15.0 5-17.5 5-12.5 5-15.0 5-17.5 5-12.55-15.0 5-17.5 5-12.5 5-15.0 5-17.5 9-31.3 9-37.5 9-43.8 9-31.3 9-37.59-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 3 1-125 1-150 1-1752-125 2-150 2-175 3-125 3-150 3-175 4-125 4-150 4-175 6-6.3 6-7.5 6-8.86-6.3 6-7.5 6-8.8 6-6.3 6-7.5 6-8.8 6-6.3 6-7.5 6-8.8 9-31.3 9-37.59-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 41-125 1-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-125 4-150 4-1756-12.5 6-15.0 6-17.5 6-12.5 6-15.0 6-17.5 6-12.5 6-15.0 6-17.5 6-12.56-15.0 6-17.5 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.59-43.8 9-31.3 9-37.5 9-43.8 5 1-125 1-150 1-175 2-125 2-150 2-175 3-1253-150 3-175 4-125 4-150 4-175 7-6.3 7-7.5 7-8.8 7-6.3 7-7.5 7-8.8 7-6.37-7.5 7-8.8 7-6.3 7-7.5 7-8.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.89-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 6 1-125 1-150 1-175 2-1252-150 2-175 3-125 3-150 3-175 4-125 4-150 4-175 7-12.5 7-15.0 7-17.57-12.5 7-15.0 7-17.5 7-12.5 7-15.0 7-17.5 7-12.5 7-15.0 7-17.5 9-31.39-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.59-43.8 7 1-125 1-150 1-175 2-125 2-150 2-175 3-125 3-150 3-175 4-1254-150 4-175 8-6.3 8-7.5 8-8.8 8-6.3 8-7.5 8-8.8 8-6.3 8-7.5 8-8.8 8-6.38-7.5 8-8.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.59-43.8 9-31.3 9-37.5 9-43.8 8 1-125 1-150 1-175 2-125 2-150 2-175 3-1253-150 3-175 4-125 4-150 4-175 8-12.5 8-15.0 8-17.5 8-12.5 8-15.0 8-17.58-12.5 8-15.0 8-17.5 8-12.5 8-15.0 8-17.5 9-31.3 9-37.5 9-43.8 9-31.39-37.5 9-43.8 9-31.3 9-37.5 9-43.8 9-31.3 9-37.5 9-43.8

[0360] The reactor block was sealed and heated to 80° C. for 4 hourswith agitation. The resulting array of polymer emulsions was allowed tocool and the reactor block opened. Visual inspection indicated thatpolymer emulsions had formed in most of the vessels of the array.

[0361] The product emulsions were diluted 100 times with THF andanalyzed using the system described above. Molecular-weight data wereobtained both from the GPC calibration curves using polystyrenestandards and from light scattering at two different angles (15° and90°). A quantitative analysis including both monomer and polymer contentcan be obtained from the peak areas. FIG. 8 shows a representative rapidgel permeation/adsorption HPLC separation of a sample, under theconditions: column, 30×10 mm, mobile phase, tetrahydrofuran at 2 mL/min,RI and LS detection.

[0362] Table 15, below, shows tabulated peak molecular weight asdetermined by this method and the following Table 16 shows the measuredconversion in each polymerization vessel determined by relative UV-VISareas of the monomer and polymer peaks, corrected for opticalabsorptivity of the components. Relative molecular weight distributioninformation (MWD) was also obtained. TABLE 15 Measured Peak MolecularWeights (kD) Col/Row 1 2 3 4 5 6 7 8 9 10 11 12 1 131 128 125 113 105 30683 615 486 256 152 244 2 122 164 195 138 N.D. 15 993 599 615 220 357270 3 200 148 125 160 618 45 539 525 512 210 181 185 4 215 238 160 148N.D. N.D. 1169 740 525 322 131 250 5 138 131 134 145 73 79 539 375 357204 205 238 6 N.D. 168 168 164 172 22 1048 845 474 190 195 226 7 232 244172 181 215 119 615 474 339 172 199 238 8 145 215 220 250 238 190 438N.D. N.D. 138 190 N.D.

[0363] TABLE 16 Conversion Data Determined from Residual MonomerDetection. Col/Row 1 2 3 4 5 6 7 8 9 10 11 12 1 98.74 99.15 99.12 93.8489.83 85.51 95.01 95.84 96.12 3.25 3.27 2.00 2 96.34 98.48 97.66 92.330.00 88.96 95.44 94.56 95.21 2.01 3.13 0.69 3 98.44 98.81 98.36 92.0186.31 81.40 93.85 94.20 96.77 3.84 7.98 3.71 4 98.89 98.80 97.53 91.280.00 0.00 93.19 94.98 95.67 1.90 0.62 4.73 5 98.61 89.76 96.06 91.5222.60 3.91 93.67 94.79 93.66 6.97 4.44 6.72 6 0.00 94.81 86.46 76.2682.36 0.00 91.55 94.19 95.09 3.10 5.18 6.06 7 99.13 89.56 93.87 84.7079.54 68.54 94.17 63.75 82.35 5.18 5.08 5.35 8 98.64 98.16 97.65 96.0781.28 81.97 94.53 0.00 0.00 7.04 2.07 0.00

Example 11 Characterizing Emulsion Samples with SEC—AdsorptionChromatography

[0364] This example demonstrates rapid characterization of emulsionparticles with rapid size-exclusion-chromatography (SEC) with a short,high-aspect ratio columns having a stationary-phase media with largepore sizes for separating polymer emulsion particles.

[0365] Retention times were used to determine R_(h) values of latexparticles injected into the chromatographic systems, using the equipmentdescribed in Example 3 and short, high-aspect ratio columns (describedbelow) packed with very a large pore size stationary phase. In thisexample, a series of standard dispersions of polystyrene latex particlesdiluted with water by a factor of 200 were injected into thechromatographic system using water as a mobile phase and a 30×10 mmchromatographic column packed with GM-GEL 3000 and GM-GEL 5000 beads(Kurita, Japan). The concentration of latex was detected by both RI andLS detectors. The RI signal was determined to be linearly dependent onthe mass of polymer in the sample.

[0366]FIG. 9 shows refractive index traces for latex particles ofdifferent sizes from this example. The average sample-throughput forthis example was less than 2 min. per sample.

Example 12 Characterizing Emulsion Samples with Rapid-fireLight-scattering

[0367] This example demonstrates rapid particle-size characterization ofemulsion particles with rapid-fire static-light-scattering (SLS)detection—without chromatographic separation.

[0368] In this example, both light scattering and refractive indextraces of various latex particles using the same chromatographic systemas described in Example 4. The particle peak areas at RI trace remainedthe same for particular concentration of particles regardless on theparticle size, while the areas of the peaks in the LS trace wereaffected significantly by particle size. The response of LS detectorrelative to that of RI is a function of the particle size. After acalibration, this dependence can be used for rapid particle sizedetermination of unknown samples.

[0369]FIG. 10 shows LS and RI traces obtained for latex particles ofdifferent sizes under the same flow conditions as in Example 11.

Example 13 Rapid Reverse-phase Chromatography w/Compositional Gradient

[0370] This example demonstrates rapid characterization of polymersamples using reverse phase liquid chromatographic separation ofpolymers based on composition differences in the mobile phase.

[0371] In a dry nitrogen atmosphere glovebox were prepared twelve stocksolutions. L-1 was synthesized from reductive coupling of4-(5-nonyl)pyridine using Pd/C catalyst at 200° C. I-2(1-chloro-1-phenylethane) was synthesized by reaction of commerciallyavailable styrene with HCl, followed by purification by distillation.All other materials were commercially available and were purified usingconventional techniques. Solution I comprised 1.5 mL of styrene.Solution II comprised 1.35 mL styrene and 0.15 mL of n-butylacrylate.Solution II comprised 1.35 mL styrene and 0.15 mL of n-butylacrylate.Solution III comprised 1.20 mL styrene and 0.30 ML of n-butylacrylate.Solution IV comprised 1.05 mL styrene and 0.45 mL of n-butylacrylate.Solution V comprised 0.90 mL styrene and 0.60 mL of n-butylacrylate.Solution VI comprised 0.75 mL styrene and 0.75 mL of n-butylacrylate.Solution VII comprised 0.60 mL styrene and 0.90 mL of n-butylacrylate.Solution VIII comprised 0.45 mL styrene and 1.05 mL of n-butylacrylate.Solution IX comprised 0.30 mL styrene and 1.20 mL of n-butylacrylate.Solution X comprised 0.15 mL styrene and 1.35 mL of n-butylacrylate.Solution XI comprised 1.50 mL of n-butylacrylate. Solution XII comprised90 mg (0.64 mmol) of 1-2, 63.4 mg (0.64 mmol) of CuCl, 584 mg (1.344mmol) of L-1, and 2 mL of diethyl carbonate. A 5-row by 11-column55-vessel glass-lined aluminum reactor block array with approximately800 uL volume per vessel, was prepared in a drybox under dry nitrogenatmosphere, and stock solutions I-XII were manually distributed to thevessels using a metering pipettor, such that column 1 elements received200 uL of solution I, column 2 elements received 200 uL of solution II,column 3 elements received 200 uL of solution III, column 4 elementsreceived 200 uL of solution IV, column 5 elements received 200 uL ofsolution V, column 6 elements received 200 uL of solution VI, column 7elements received 200 uL of solution VII, column 8 elements received 200uL of solution VIII, column 9 elements received 200 uL of solution IX,column 10 elements received 200 uL of solution X, column 11 elementsreceived 200 uL of solution XI. Solution XII was then added to allelements such that row 1 received 50 μL, row 2 received 40 SAL, row 3received 30 uL, row 4 received 20 uL and row 5 received 10 uL. Thereactor block array was sealed using a teflon film covering a siliconrubber against an aluminum cap.

[0372] The array was then heated to 140° C. for 15 hr with agitationprovided by an orbital shaker. The reaction block was allowed to cool,and to each vessel was added THF such that the total volume reached 0.8mL, and the block was sealed and heated at 110° C. with orbital shakingfor approximately 1 hr, to allow formation of uniform, fluid solution,and the reactor block was allowed to cool. This library of randomcopolymers of styrene and n-butylacrylate was expected to producepolymers with a range of molecular weights and compositions, which weretested with the following system.

[0373] Adsorption chromatography was used for separation of variouscomponents of the reaction mixtures that contained the comonomers,(co)polymers, solvents and catalyst components. Good separation wasachieved in 60 seconds per sample using a short, high-aspect ratioreversed-phase column and gradient of THF in water with a concaveprofile. The specific gradient profile allows to separate smallmolecules with similar retention behavior from each other as well aselute a highly retained polymer in a very short time. Columns of varioussizes, porosities and chemistries were used for this purpose includingpolystyrene-based monoliths and silica-based porous beads.

[0374] Combination of optimum column and mobile phase parameters leadsto a much faster separation then experienced before and allows thetechnique to be used for characterization of the polymerizationlibraries. The best results were achieved with short cartridges packedwith 10 μm octadecylsilica beads. The library of 96 polymer samplemixtures was analyzed in 144 min (including diluting samples,chromatography and saving the chromatograms)—demonstrating an averagesample throughput of about 1.5 minutes per sample.

[0375] In this example, samples containing styrene, butylacrylate,(co)polymer, initiator and solvent at various concentrations wereinjected into a 30×4.6 mm precolumn cartridge RP-18 (Brownlee)equilibrated by 27% tetrahydrofuran at 10 mL/min. Then the percentage oftetrahydrofuran in mobile phase was changed using a concave gradientprofile from 27 to 100% tetrahydrofuran. The chromatographic system usedfor this example was the same as that described in Example 3, however,equipped with a UV-VIS detector only. The solvent and monomers areeluted within a first few percent of tetrahydrofuran, polymer requiresmuch higher percentage of tetrahydrofuran to be eluted. All five peaksrepresenting the particular components of the mixtures were elutedwithin 60 seconds.

Example 14 Comparison of Rapid GPC and Conventional GPC

[0376] This example demonstrates correlation between rapid liquidchromatography (using a short, high-aspect ratio column) andconventional GPC.

[0377] The same synthetic procedure as in Example 8 was carried outusing a robotic sampler in an inert atmosphere drybox, requiringapproximately 20 min. to prepare the reaction array. Similar processingof the array was carried out as in Example 8.

[0378] Row six of the array was analyzed by RFLS as in Examples 5 and 9to determine values of M_(w). Row six was also analyzed by conventionalGPC using two mixed bed columns (Polymer Labs, 7.5×300 mm mixed CPL-gel). THF was used as the eluant in both cases.

[0379] Comparisons of M_(w) values obtained by both methods are shown bythe following Table 17. TABLE 17 Comparison of M_(w) Values from RFLSand Conventional GPC RFLS GPC Sample (M_(w), kD) (M_(w), kD) 1 79.7 83.82 45.1 52.4 3 42.8 46.4 4 38.9 N.D. 5 39.7 45.7 6 37.4 40.3 7 37.2 41.98 34.9 39.9 9 35.5 38.4 10 33.9 34.2 11 34.3 37.4

[0380] As can be seen from this table, the rapid GPC protocols disclosedherein provide M_(w) values in agreement with traditional GPC.

Example 15 Rapid Size Exclusion Chromatography

[0381] This example demonstrates the characterization of a plurality ofpolystyrene standards using rapid size exclusion chromatography. Thesample-throughput was 2 minutes per sample.

[0382] Two short, high-aspect ratio columns (0.8 cm×3 cm) were employedin series. The first column was packed with Suprema Gel 30 Å and thesecond column was packed with Suprema Gel 1000 Å (Polymer StandardService, Germany). The mobile-phase solvent was THF at a flowrate of 2ml/min. Sample preparation was the same as in Example 17. The polymersamples (20 μl) were serially injected at two minute intervals (withoutbeing overlaid). The separated samples or components thereof weredetected with a UV-VIS detector at 220 nm.

[0383]FIGS. 11A and 11B shows the results—overlaid as a single trace(FIG. 11A) and the corresponding calibration curve (FIG. 11B). Goodlinearity of the calibration curve is demonstrated.

Example 16 Rapid Size Exclusion Chromatography with Enhanced Resolution

[0384] This example demonstrates the characterization of a plurality ofbutyl rubber (polyisobutylene) samples using size exclusionchromatography with overlaid injection and enhanced resolution. Thesample-throughput was 1½ minutes per sample.

[0385] A single, conventional chromatography column (0.75 cm×30 cm) waspacked with PL Gel Mixed-B (Polymer Labs). The mobile-phase solvent wastoluene at a flowrate of 4 ml/min. The system was calibrated using theindirect calibration polystyrene standards and protocols of Example 26.Sample preparation was the same as in Example 17. The polymer samples(50 μl) were serially injected at 90 second intervals (with overlaidinjection). The separated samples or components thereof were detectedwith an ELSD detector at 120° C. and 7 l/min of air.

[0386]FIG. 12A through FIG. 12C show the data from the experiment. FIG.12A shows the chromatographs of each of the samples—electronicallyoverlaid on a single trace. The chromatograph for the “single-shot”indirect calibration standard is shown in FIG. 12B and the correspondingcalibration curve is shown in FIG. 12C. Significantly, a relativehigh-molecular weight polyisobutylene was identified (M_(peak)=154,288;M_(w)=199,123; M_(w)=46,406; PDI˜4.3) and distinguished from other,lower molecular weight samples.

Example 17 Rapid Size Exclusion Chromatography with Enhanced Resolution

[0387] This example demonstrates the characterization of a plurality ofpolyisobutylene samples using accelerated size exclusion chromatographywith overlaid injection. The sample-throughput was 8 minutes per sample.

[0388] A series of three identical conventional chromatography column(0.75 cm×30 cm) were employed, each of which was packed with PL GelMixed-B (Polymer Labs). The mobile-phase solvent was toluene at aflowrate of 2 ml/min. The system was calibrated using polystyrenestandards. Sample preparation (dilution, mixing) was effected on eachsucceeding sample while each preceding sample was being separated. Thepolymer samples (50 μl) were serially injected at 8 minute intervals(with overlaid injection). The separated samples or components thereofwere detected with an ELSD detector at 120° C. and 7 l/min of air.

[0389]FIG. 13 is a representative chromatograph from one of the samples.As shown in FIG. 13, the representative sample comprised an earliereluting polymer component (M_(peak)=67,285; M_(w)=75,162; M_(w)=38,106;PDI˜2.0) and a later eluting lower molecular-weight component(M_(peak)=1,736).

[0390] The same library of polymer samples was characterized a secondtime with the same liquid chromatography system except that the mobilephase was THF at 2 ml/min and the ELSD detector was at 50° C. and 7l/min of air. Similar results (not shown) were obtained.

Example 18 Comparison of Rapid SEC, Enhanced Rapid SEC, and AcceleratedSEC

[0391] This example demonstrates a comparison between three preferredembodiments of the invention: rapid size exclusion chromatography (SEC),rapid SEC with enhanced resolution and accelerated SEC. Theseembodiments differ, in general, with respect to sample throughput and,in some aspects, information quality, as explained below.

Example 18A Comparison of Accelerated SEC and Rapid SEC

[0392] A combinatorial library of polystyrene polymer samples—preparedin emulsions with varying ratios of monomer to initiator—werecharacterized with two different liquid chromatography approaches:accelerated SEC and rapid SEC—adsorption chromatography.

[0393] The accelerated SEC liquid chromatography system wassubstantially similar to that described in Example 17, with asample-throughput of 8 minutes per sample and with complete molecularweight determination (M_(peak), M_(w), M_(n), PDI, and molecular weightdistribution shape). The rapid SEC-adsorption liquid chromatographysystem was substantially similar to that described in Example 20, exceptwith a sample-throughput of about 1-2 minutes per sample with limitedmolecular weight determination (M_(peak), M_(w), and estimate of PDI).

[0394]FIGS. 14A and 14B show the determined weight-average molecularweight for each of the samples of the library as characterized using theaccelerated SEC (FIG. 14A) and the rapid SEC (FIG. 14B) systems. Theweight-average molecular weight determined by these techniques issubstantially the same—demonstrating that the rapid SEC system,operating with a throughput of about 1-2 minutes per sample, is rigorousfor determination of M_(w). The techniques varied, however, with respectto the accuracy of determined PDI values (data not shown).

Example 18B Comparison of Accelerated SEC and Enhanced Rapid SEC

[0395] A combinatorial library of butyl rubber (polyisobutylene) polymersamples were prepared, and then characterized with two different liquidchromatography approaches: accelerated SEC and enhanced rapid SEC (alsoreferred to herein as “rapid SEC with enhanced resolution”).

[0396] The accelerated SEC liquid chromatography system wassubstantially similar to that described in Example 17, with asample-throughput of 8 minutes per sample and with complete molecularweight determination (M_(peak), M_(w), M_(n), PDI, and molecular weightdistribution shape) and conversion determination. The rapid SEC liquidchromatography system was substantially similar to that described inExample 16, with a sample-throughput of about 1½ minutes per sample andwith reasonably complete molecular weight determination (M_(peak),M_(w), and good estimate of PDI) and conversion determination.

[0397]FIGS. 15A through 15F show the resulting data. FIGS. 15A through15C show the determined weight-average molecular weight (FIG. 15A), thedetermined polydispersity index (FIG. 15B) and the determined conversion(FIG. 15C) for each of the samples of the library as characterized usingthe accelerated SEC system. FIGS. 15D through 15F show the determinedweight-average molecular weight (FIG. 15D), the determinedpolydispersity index (FIG. 15E) and the determined conversion (FIG. 15F)for each of the samples of the library as characterized using theenhanced rapid SEC system. Comparison of the results demonstrates thatthe determined weight-average molecular weight and the determinedconversion are substantially the same for each of these techniques.Although differences can be observed between the determined values forthe polydispersity indexes of the two characterizations systems, trendsin PDI values are observable and substantially the same for the twocharacterization systems.

Example 19 Comparison of ELSD Detector and RI Detector

[0398] This example demonstrates a comparison between an evaporativelight-scattering detector (ELSD), sometimes alternatively referred to asan evaporative mass detector (EMD), and a refractive index (RI)detector. More specifically, this example demonstrates the principle ofusing a low-molecular weight insensitive detector, such as an ELSD, fordetection in liquid chromatography or flow injection analysis systems.

[0399]FIGS. 16A and 16B show chromatographic traces for the same polymersample characterized in two different liquid chromatography systems thatwere identical except with respect to the detector—one system employinga RI detector and a second system employing an ELSD detector. Comparisonof these traces (FIG. 16A, FIG. 16B) shows that the polymer sample had arelatively high-molecular weight component (M_(peak)=244,794) and arelatively low-molecular weight component (M_(peak)=114). Although bothdetectors characterized the relatively high-molecular weight component,the ELSD detector was insensitive to the relatively low-molecular weightcomponent.

[0400] As discussed above, such insensitivity can be advantageouslyemployed in connection with the invention, particularly with respect toserial overlaid injection of a preceding sample and a succeeding sample.Unlike the RI detector, the ELSD detector can detect the leading edge ofthe succeeding sample sooner, without interference from the trailingedge of the preceding sample.

Example 20 Rapid SEC—Adsorption Chromatography

[0401] This example demonstrates the characterization of a plurality ofemulsion polymer samples using rapid size exclusion chromatography (SEC)in combination with adsorption chromatography to determine molecularweight and conversion. The sample-throughput was 2-3 minutes per sample.

[0402] Two short, high-aspect ratio columns (0.8 cm×3 cm) were employedin series. The first column was packed with Suprema Gel 30 Å and thesecond column was packed with Suprema Gel 1000 Å (Polymer StandardService, Germany). The mobile-phase solvent was THF at a flowrate of 2ml/min. Sample preparation was the same as in Example 17. The emulsionpolymer samples (polystyrene, polymethylmethacrylate, polybutylacrylateand polyvinylacetate) were serially injected at 2-3 minute intervals(without being overlaid). The separated samples or components thereofwere detected.

[0403]FIGS. 17A and 17B shows the determined conversion (FIG. 17A) andthe determined weight-average molecular weight (FIG. 17B) for thepolystyrene samples (columns 1-4), the polymethylmethacrylate samples(columns 4-6), the polybutylacrylate samples (columns 7-9) and thepolyvinylacetate samples (columns 10-12). These data demonstrate thatSEC-adsorption chromatography can be effectively employed to determineboth molecular weight and conversion with high sample-throughput.

Example 21 High—Temperature Characterization of Polymers

[0404] This example demonstrates the characterization of a plurality ofpolystyrene and polyethylene calibration standards usinghigh-temperature liquid chromatography.

[0405] The experimental set-up was substantially as shown in FIG. 6 anddescribed in connection therewith and as follows. The auto-sampler 104′was located outside of a heated oven 112, and was equipped with a long,thermostatically-controlled heated probe 201 maintained at a temperatureof 140° C. The heated probe was substantially as shown in FIG. 5A anddescribed in connection therewith. The sample container 202 was likewiseheated and maintained at a temperature of 140° C. The loading port 204,transfer line 206, injection valve 210, in-line filter (0.2 μl, notshown), and column 102 resided in the oven 112 and maintained at atemperature ranging from 140° C. to 160° C. The injection valve 210 wasan eight-port valve substantially as shown in FIG. 3 and described inconnection therewith, with each of the sample loops having a volume ofabout 200 μl. The column was a high-aspect ratio column (2.5 cm×5 cm)packed with PL Gel Mixed-B (Polymer Labs). For the experiments ofExample 21A only, an in-line flow-splitter (not shown) was positionedafter the column and the before the detector. The flow-splitter residedin the oven, and split the separated sample stream at a ratio of about1:15 (detector:waste). For both examples 21A and 21B, an external ELSDdetector resided outside of the heated oven 112, and was in fluidcommunication with the column 102 (or flow-splitter) by means of aheated transfer line.

[0406] The following commercially available calibration standards wereserially introduced into the liquid chromatography system by seriallywithdrawing the samples from the sample container and delivering thesamples through oven aperture 113 to the loading port 204: PolyethylenePolystyrene (nominal Mw) (nominal Mw) 1,230 1,370 2,010 4,950 16,50010,900 36,500 29,000 76,500 68,600 91,500 215,000 145,500 527,0001,253,000 3,220,000

Example 21A Rapid Size-exclusion Chromatography—First Conditions

[0407] In a first experiment, molecular weight was determined with asample-throughput of 70 seconds per sample.

[0408] Briefly, the mobile-phase solvent was trichlorobenzene at aflowrate of 9 ml/min. Sample preparation (dissolution intrichlorobenzene) was effected on each succeeding sample while eachpreceding sample was being separated. The polymer samples were seriallyinjected at 70 second intervals (with overlaid injection). The transferline for transferring the samples to the ELSD was maintained at about165° C. The samples or components thereof were detected with an ELSDdetector at 180° C. (nebulizer temperature)/250° C. (evaporatortemperature) and 1.8 I/min of nitrogen.

[0409]FIGS. 18A and 18B show the results as a chromatograph for thepolystyrene standards overlaid as a single trace (FIG. 18A) and as acalibration curve for representative polyethylene standards (FIG. 18B).Linearity of the calibration curve is demonstrated.

Example 21B Rapid Size-exclusion Chromatography—Second Conditions

[0410] In a second experiment, molecular weight was determined with asample-throughput of 2¼ minutes per sample.

[0411] Briefly, the mobile-phase solvent was o-dichlorobenzene at aflowrate of 10 ml/min. Sample preparation (dissolution intrichlorobenzene) was effected on each succeeding sample while eachpreceding sample was being separated. The polymer samples were seriallyinjected at 2.2 minute intervals (without overlaid injection). Thetransfer line for transferring the samples to the ELSD was maintained atabout 160° C. The samples or components thereof were detected with anELSD detector at 160° C. (nebulizer temperature)/250° C. (evaporatortemperature) and 2.0 l/min of nitrogen.

[0412]FIGS. 19A and 19B show the results as a chromatograph forrepresentative polystyrene standards and polyethylene standards overlaidas a single trace (FIG. 19A) and as a calibration curve forrepresentative polyethylene standards (FIG. 19B). Linearity of thecalibration curve is demonstrated.

Example 22 High-temperature HPLC with Mobile-phase Temperature Gradient

[0413] This example demonstrates the principle for high-temperaturecharacterization of a polyethylene polymer sample using liquidchromatography with a mobile-phase temperature gradient.

[0414] A single, short, high-aspect ratio column (0.8 cm×5 cm) containeda polystyrene monolith as the separation medium and resided in a PL-210HT-GPC oven maintained at 140° C. The system was configuredsubstantially as shown in FIG. 6 and described in connection therewithand as follows. Two mobile-phase reservoirs 114, 120 were provided andequipped with two Waters 515 pumps 116, 118. A “mobile-phase A”reservoir 114 feeding pump 116 (hereinafter “pump A”) comprisedtrichlorobenzene (TCB) and, in operation, was configured to pumpmobile-phase A through the injection valve 210 (100) and through theoven, whereby the mobile-phase A was heated to become the hot mobilephase (i.e., hot TCB). A “mobile-phase B” reservoir 120 feeding pump 118(hereinafter “pump B”) also comprised trichlorobenzene, and inoperation, was configured to pump mobile-phase B to bypass most of theheated environment, and to enter the oven immediately prior to thecolumn 102 as an essentially ambient-temperature mobile phase (i.e.,cold TCB). Detection was effected with a PD 2000 light-scatteringdetector (90°).

[0415] In a first experiment, a polyethylene polymer sample(M_(w)=30,000) was introduced into the system with mobile-phase A (only)at a flow rate of 3 ml/min, such that the sample entered the column withthe hot TCB mobile phase. The mobile-phase was maintained as the hot TCBduring the entire experiment.

[0416] In a second experiment, a polyethylene polymer sample(M_(w)=30,000) was introduced into the system with mobile phaseinitially configured as mobile-phase B at a flow rate of 3 ml/min, suchthat the sample entered the column with the cold TCB mobile phase. Themobile-phase was maintained as the cold TCB for two minutes, at whichtime the system was reconfigured to switch to mobile-phase B at 3 ml/minsuch that the sample was eluted shortly thereafter with hotTCB—essentially effecting a mobile-phase temperature step-gradient (fromcold TCB to hot TCB).

[0417]FIG. 20 shows the chromatograph—superimposed (overlaid) for thefirst and second experiments. Comparison of the two traces demonstratesthat elution of the polyethylene sample was effectively controlled bycontrolling the temperature of the mobile phase. Hence, mobile-phasetemperature gradients can be employed in connection with thehigh-temperature characterization of polymers.

Example 23 Very Rapid Flow-injection Light-scattering

[0418] This example demonstrates the characterization of polymer libraryusing a very rapid flow-injection light-scattering (FILS) system. Thesample throughput was 8 seconds per sample. This example alsodemonstrates the advantage of using a low-molecular weight insensitivedetector, particularly an ELSD, over a static light-scattering (SLS)detector (90°) in such a FILS system. This example demonstrates,moreover, that the data from an entire 96-member library of polymersamples can be collected, processed and then stored in a single datafile.

[0419] A 96-member polymer library was introduced into a flow-injectionlight-scattering system configured substantially as shown in FIG. 7C anddescribed in connection therewith—with a 0.2 μl in-line filter in place,but no chromatographic column. The polymer samples were seriallyinjected at intervals of 8 seconds into a methyl-tert-Butyl Ether mobilephase at a flow rate of 4 ml/min.

[0420] In a first experiment, the polymer samples were detected with a90° SLS (using Wyatt's MiniDawn). In a second experiment, the polymersamples were detected with an ELSD (PL-1000) at 50° C. and 1.5 l/min gasflowrate. In both the first and second experiments, the data for theentire polymer library (96 samples) was collected and stored as a singledata file (in about 13 minutes total cumulative time).

[0421]FIGS. 21A and 21B show the resulting chromatographs for the 96polymer samples using the SLS detector (FIG. 21A) and the ELSD (FIG.21B). Comparison of these chromatographs demonstrates that the ELSD wasable to differentiate between various polymer samples of the librarywith a sample-throughput of 8 seconds per sample.

Example 24 Variable-flow Light-scattering

[0422] This example demonstrates variable-flow light scatteringapproaches for characterizing a library of methacrylate emulsionpolymers prepared by batch free-radical emulsion polymerization. Thesample-throughput was 35 seconds per sample.

[0423] The flow-injection analysis system was substantially as shown inFIG. 7C and described in connection therewith. Specifically, the systemincluded an eight-port injection valve 210 (Valco Instruments), an HPLCpump 116 (Waters 515), stainless steel capillaries, an in-line filter212 (2 μm, Valco Instruments), and a combined SLS/DLS/RI flow-throughdetector (Precision Detectors, PD2000/QELS)—with no chromatographiccolumn.

[0424] The system was calibrated with monodisperse PS latex standardshaving R_(h) of 9.5, 25, 51, and 102 nm in ultrapure water (DukeScientific, Palo Alto, Calif.).

[0425] The emulsion samples were prepared (substantially in the mannerdescribed in Example 17) by dilution with ultrapure water to aconcentration of about 0.001 wt % using an auto-sampler substantially asshown in FIG. 4 and described in connection therewith. The emulsionpolymer samples (20 μl) were serially injected into an ultra-pure watermobile phase at intervals of 35 seconds. The mobile-phase flow rate wascontrolled by the pump 116 which, in turn, was controlled bymicroprocessors 350, 352, to provide an advancing flowrate, V_(ADVANCE)of 1.5 l/min that advanced the sample into the detection cavity of thelight-scattering cell very rapidly—within about a few seconds. Thestatic light-scattering detector signal was monitored as an indicationof the leading edge of the sample entering the detection cavity. Anincrease of the static light-scattering detector signal to 2.5 V abovethe baseline voltage caused the microprocessor to reduce the flowrate ofthe mobile phase to a detection flow rate V_(DETECT) of 0.1 ml/min,which was subsequently maintained for a detection period of 15 seconds.

[0426] During this detection period, dynamic light-scatteringmeasurements were taken at a temperature of 35° C. using the correlatorboard of the PD2000/QELS instrument (Software NTP32, version 0.98.005)as follows: 10 μsec sampling times; dilation factor of 4; and a totalmeasurement time of 1.5 seconds per data point. Hence, 10 independentmeasurements of R_(h) were taken per sample during the 15 seconddetection period.

[0427] Following the detection period, the flow-rate was increased to apassing flowrate, V_(PASS) of 1.5 l/min—the same as the advancingflowrate, VADVANCE for a period of about 15 seconds. The whole cycle,represented schematically in FIG. 7D, was then repeated for each of thepolymer samples.

[0428] The post-acquisition data analysis and processing for the polymerlibrary was performed automatically. To ensure that measurementscorresponded to a particular sample in the detection cavity (i.e., inthe scattering volume), measurements taken during the detection periodare only considered for further processing and analysis when the SLSsignal clearly exceeds the aforementioned baseline voltage. From thoseconsidered measurements, the first 3 measurements taken during thedetection period were discarded to ensure that uniform flow-conditionshad been established with respect to the processed data. The R_(h) for asingle measurement point for the sample were then determined byaveraging the remaining 7 individual measurements and removing erroneousspikes and noise, where applicable.

[0429] The determined hydrodynamic radius R_(h) (nm) for each of themembers of the emulsion library are shown in Table 18. TABLE 18Determined Average R_(h) (nm) for Emulsion Library 1 2 3 4 5 6 7 8 9 1011 12 A 40.3 43.8 48.3 50.6 50.4 56.5 56.6 56.6 54.1 56.9 56.9 61.6 B48.3 51.8 52.5 53.4 54.0 55.4 54.7 53.8 59.4 59.8 50.9 48.7 C 53.1 53.854.2 54.2 55.9 55.0 56.4 61.0 55.1 52.4 47.2 48.2 D 52.6 53.9 56.1 55.456.0 60.7 57.6 56.0 48.9 50.7 49.4 47.8 E 56.3 55.7 56.4 56.9 55.5 57.754.8 52.4 51.4 50.9 48.7 49.3 F 56.7 56.5 57.2 62.4 55.3 54.0 52.2 51.953.0 49.9 50.2 49.4 G 56.8 59.7 59.3 57.9 54.5 52.9 50.3 48.4 48.8 46.751.3 50.1 H 63.3 61.5 58.7 58.9 52.7 52.4 52.4 49.1 50.3 48.8 47.6 48.4

Example 25 Single-shot Indirect Calibration

[0430] This example demonstrates single-shot indirect calibration of aliquid chromatography system.

[0431] Conventional Commercially-available Calibration Standards

[0432]FIG. 22A shows the chromatograph resulting from single-shotcalibration using eight pooled, commercially-available polyisobutylenestandards (FIG. 22A).

[0433] Although the commercially available standards employed were eachconsidered to be and were sold as “narrow-band” standards, FIG. 22Ademonstrates that the polyisobutylene standards could not be effectivelyemployed in single-shot (pooled standard) calibration. As shown therein,the chromatograph shows only three broad peaks—without resolution of atleast five of the polyisobutylene standards.

[0434] Single-shot Calibration Standards for Polyisobutylene

[0435] Because a single-shot calibration is generally advantageous withrespect to system accuracy, expense and speed, a set of polystyrenestandards suitable for use, when pooled, as a single-shot standards forpolyisobutylene were developed as follows.

[0436] A set of nine commercially available polyisobutylene standardshaving known molecular weights were individually and seriallycharacterized with the liquid chromatography system (in toluene andunder the same conditions) to determine the retention time of theindividual standards. The nine polyisobutylene standards and theircorresponding (known) molecular weight were:

[0437] Polyisobutylene Standards (M_(peak))

[0438] (1) 1000

[0439] (2) 4,000

[0440] (3) 9,500

[0441] (4) 26,000

[0442] (5) 67,000

[0443] (6) 202,500

[0444] (7) 539,500

[0445] (8)1,300,000

[0446] (9) 3,640,000

[0447] After all of the standards had been run individually through thesystem (nine runs total), the data was assembled to form an absolutepolyisobutylene (PIB) calibration based on the individual runs. FIG. 23Ashows the individually determined retention-time data plotted againstthe corresponding known molecular weight—referred to herein as an“absolute” or “direct” polyisobutylene (PIB) calibration curve. The datafor each of the PIB standards ((1) through (9)) are labeled on thechromatograph.

[0448] A set of commercially available polystyrene standards havingknown molecular weights were then evaluated with the same system underthe same conditions (data not shown). Those polystyrene standards havingretention times that were substantially the same as the retention timesfor the nine PIB standards were selected, with the resulting correlationbeing as follows: Polyisobutylene Standards Selected PolystyreneStandards (M_(peak)) (M_(peak)) (1) 1000 (1) 1,350 (2) 4,000 (2) 4,950(3) 9,500 (3) 10,850 (4) 26,000 (4) 28,500 (5) 67,000 (5) 70,600 (6)202,500 (6) 214,500 (7) 539,500 (7) 520,000 (8) 1,300,000 (8) 1,290,000(9) 3,640,000 (9) 3,220,000

[0449] A set of eight of the nine selected polystyrene (PS) standardswere then pooled to form a set of polystyrene standards (the smallmolecular weight standard being omitted), that were, effectively, acomposition suitable for single-shot indirect calibration forpolyisobutylene. These pooled PS standards were then characterized withthe chromatography system with the same conditions. FIG. 22B shows theresulting chromatograph for the set of eight, pooled polystyrenestandards that correspond to (i.e., have the same hydrodynamic volumeas) the PEB standards of known molecular weight. As expected, theindirect PS standards for PIB are readily resolved by thechromatographic system. Significantly, however, these well-resolvedsamples are hydrodynamic-volume equivalents of the eight PIB standardsthat could not be resolved by the system when loaded as a single shot.(See FIG. 22A, and compare to FIG. 22B).

[0450] The aforementioned steps were repeated in substantially the samemanner with the same system for a second set of polyisobutylenestandards of known (different) molecular weights.

[0451] An indirect PEB calibration curve was then formed, by plottingthe retention time determined from the single-shot run with the pool ofthe selected polystyrene standards—against the molecular weight of thecorresponding polyisobutylene standards. FIG. 23B shows the indirect PIBcalibration curve. Comparison of FIG. 23A (absolute PEB calibrationcurve) and FIG. 23B (indirect PEB calibration curve) demonstrates thatthe calibration curve determined from the single-shot indirectcalibration standards for polyisobutylene is equivalent to thecalibration curve laboriously derived from the serial direct calibrationof the PEB standards.

Example 26 Parallel Characterization of Polymers with Dynamic LightScattering

[0452] This example demonstrates the characterization of a 96-memberlibrary of emulsion polymers in a parallel manner—using a plurality ofdynamic light-scattering (DLS) detector probes. Because the number ofDLS probes was less than the total number of samples, the library wasevaluated in a serial-parallel (i.e., semi-parallel) manner. The averagesample-throughput for characterizing the entire library in this mannerwas about 5-15 seconds per sample.

[0453] The emulsion library was the same as used in connection withExample 24, and was prepared (diluted) as described therein. Nofiltering was performed on the dispersion before the measurements.

[0454] A parallel DLS system used for characterizing the library ofpolymer samples was configured substantially as shown in FIG. 24 anddescribed in connection therewith. Briefly, the system comprised anarray 410 of two DLS probes 420 supported in parallel by a commonsupport structure. Each probe 420 included a transmitting optical fiber425, 425′ and a receiving optical fiber 430, 430′.

[0455] Two single-mode fiber couplers, also referred to as optics (notshown), were used for transmitting an incident light and collecting ascattered light. These couplers consisted of a gradient refractive index(GRIN) lens aligned to a single-mode optical fiber. (Such couplers aretypically used for coupling the output of a laser diode into an opticalfiber.). For the DLS application, a focal length of 10 mm for bothsource and detector optics were chosen. The optics were mounted at anangle of 45 degrees with respect to each other giving a measurementangle of 135 degrees.

[0456] A HeNe laser 435 provided laser light at 632.8 nm wavelength (5mW, Melles Griot). The laser light was coupled into the transmittingoptical fiber in the fiber-optics array 440 and delivered into thesample 20 by the first optic. The scattered light was collected by thesecond optic. Unlike the immersed-probe configuration shown in FIG. 24,the measurements were done in a non-immersion, non-contact mode bymounting the probes approximately 5 mm above the liquid surface, suchthat the laser beam was delivered and the scattered light was collectedthrough the liquid surface.

[0457] The scattered light collected by the second optic was coupledinto the receiving optical fiber. The receiving optical fiber wasconnected to an avalanche photodiode (SPCM, EG&G, Canada). Measurementswere performed at a temperature of 21° C. The measurements and photonautocorrelation were taken in a serial manner with a data acquisitiontime of 5 seconds per sample using a commercial autocorrelator board(ALV 5000/E, ALV GmbH Langen, Germany). The autocorrelation function wasanalyzed by a second order cumulant analysis (ALV Software, Version 2.0)and the hydrodynamic radius R_(h) and the polydispersity index (PDI)were determined.

[0458] These data are presented in Tables 19 and 20, respectively. Acomparison of Table 19 with Table 18 (Ex. 24) demonstrates that theaverage hydrodynamic radii determined by this parallel DLS,non-immersion detection approach correlate well with those valuesdetermined by variable flow-injection analysis.

[0459] Including time for positioning the sample under the probe, thetotal measurement took between 5 and 15 seconds per well. TABLE 19Determined Average R_(h) (nm) for Emulsion Polymer Library 1 2 3 4 5 6 78 9 10 11 12 A 38.8 40.4 45.9 46.4 49.5 48.9 50.1 56.2 50.1 51.9 53.254.8 B 43.8 48.1 52.7 50.6 50.9 52.5 52.1 51.3 54.8 55.8 48.5 45.2 C48.5 50.4 51.8 50.3 53.2 51.2 54.1 59.2 54.3 49.3 48.3 47.2 D 50.5 52.252.9 51.7 52.9 58.1 59.2 53.9 49.1 50.8 48.6 46.2 E 56.0 53.6 54.7 55.058.7 56.3 52.6 48.6 47.0 49.1 47.5 48.4 F 51.0 54.2 56.2 61.0 54.2 50.950.9 52.2 49.0 50.3 46.8 48.2 G 53.8 55.5 56.3 53.6 53.1 52.8 49.4 45.648.9 43.8 45.7 48.2 H 58.2 56.1 54.8 55.1 50.7 49.1 49.4 47.1 49.6 44.744.4 46.3

[0460] TABLE 18 Determined PDI (cumulant analysis) for Emulsion PolymerLibrary 1 2 3 4 5 6 7 8 9 10 11 12 A 0.08 0.08 0.03 0.03 0.01 0.09 0.080.06 0.06 0.02 0.11 0.05 B 0.09 0.14 0.25 0.11 0.15 0.07 0.15 0.13 0.040.04 0.02 0.12 C 0.08 0.01 0.01 0.01 0.06 0.07 0.05 0.11 0.02 0.02 <0.010.06 D 0.06 0.08 0.03 0.09 0.06 0.02 0.12 0.09 0.05 0.01 <0.01 0.08 E0.09 0.08 0.03 0.03 0.13 0.04 0.01 0.01 0.02 0.06 0.01 0.02 F <0.01 0.030.03 0.08 0.07 0.03 0.04 0.03 0.11 0.06 0.04 0.07 G 0.08 0.08 0.06 0.060.06 0.09 0.05 <0.01 0.09 0.10 0.12 0.09 H 0.05 0.06 0.01 0.06 0.05 0.050.10 0.01 0.15 <0.01 0.14 0.09

[0461] In light of the detailed description of the invention and theexamples presented above, it can be appreciated that the several objectsof the invention are achieved.

[0462] The explanations and illustrations presented herein are intendedto acquaint others skilled in the art with the invention, itsprinciples, and its practical application. Those skilled in the art mayadapt and apply the invention in its numerous forms, as may be bestsuited to the requirements of a particular use. Accordingly, thespecific embodiments of the present invention as set forth are notintended as being exhaustive or limiting of the invention.

We claim:
 1. A method for characterizing a polymer sample, the methodcomprising withdrawing a polymer sample from a sample container into aninjection probe of an auto-sampler, the injection probe being heated tomaintain the withdrawn sample at a temperature of not less than about75° C. while resident in the injection probe, the heated injection proberesiding in a first environment maintained at about ambient temperaturewhile withdrawing the polymer sample, loading at least a portion of thewithdrawn sample into an injection port or a loading port of a liquidchromatography system, the injection port or loading port beingadaptable for fluid communication with a chromatographic column, thechromatographic column residing in a heated second environmentmaintained at a temperature of not less than about 75° C., injecting theloaded sample into a mobile phase of the liquid chromatography system,maintaining the sample at a temperature of not less than about 75° C.during a period of time including from when the sample is withdrawn fromthe sample container to when the sample is within the heated secondenvironment, chromatographically separating the injected sample, anddetecting a property of the sample or of a component thereof.
 2. Themethod of claim 1 further comprising beating the sample container tomaintain the polymer sample at a temperature of not less than about 75°C. while the sample is resident in the container.
 3. The method of claim1 wherein the injection probe is heated to maintain the withdrawn sampleat a temperature of not less than about 100° C. while resident in theinjection probe, the heated second environment is maintained at atemperature of not less than about 100° C., and the sample is maintainedat a temperature of not less than about 100° C. during a period of timeincluding from when the sample is withdrawn from the sample container towhen the sample is injected into the portion of the liquidchromatography system residing in the heated second environment.
 4. Themethod of claim 1 wherein the injection probe is heated to maintain thewithdrawn sample at a temperature of not less than about 125° C. whileresident in the injection probe, the heated second environment ismaintained at a temperature of not less than about 125° C., and thesample is maintained at a temperature of not less than about 125° C.during a period of time including from when the sample is withdrawn fromthe sample container to when the sample is injected into the portion ofthe liquid chromatography system residing in the heated secondenvironment.
 5. The method of claim 1 wherein the injection probe isheated to maintain the withdrawn sample at a temperature of not lessthan about 150° C. while resident in the injection probe, the heatedsecond environment is maintained at a temperature of not less than about150° C., and the sample is maintained at a temperature of not less thanabout 150° C. during a period of time including from when the sample iswithdrawn from the sample container to when the sample is injected intothe portion of the liquid chromatography system residing in the heatedsecond environment.
 6. The method of claim 1 wherein the injection portor loading port resides in the first environment maintained at aboutambient temperature, the method further comprising advancing theinjected sample toward the chromatographic column through a transferline providing fluid communication between the injection port or loadingport and the chromatographic column, and heating the transfer line tomaintain the injected sample at a temperature of not less than about 75°C. while resident in the transfer line.
 7. The method of claim 1 whereinthe injection port or the loading port resides in the heated secondenvironment maintained at a temperature of not less than about 75° C. 8.A method for characterizing a polymer sample, the method comprisingwithdrawing a polymer sample from a sample container into an injectionprobe of an auto-sampler, the injection probe being heated to maintainthe withdrawn sample at a temperature of not less than about 75° C.while resident in the injection probe, the heated injection proberesiding in a first environment maintained at about ambient temperature,loading at least a portion of the withdrawn sample into an injectionport or a loading port of a flow-injection analysis system, theinjection port being adaptable for fluid communication with acontinuous-flow detector, injecting the loaded sample into a mobilephase of the flow-injection analysis system, detecting a property of thesample or of a component thereof, and maintaining the sample at atemperature of not less than about 75° C. during a period of timeincluding from when the sample is withdrawn from the sample container towhen the property of the sample or of a component thereof is detected.9. A method for characterizing a polymer sample, the method comprisingseparating at least one sample component of a polymer sample from othersample components thereof in a chromatographic column residing in aheated environment, maintaining the heated environment at a temperatureof not less than about 75° C., allowing at least about ±0.5° C.variation in the temperature of the heated environment, and detecting aproperty of at least one of the separated sample components with adetector insensitive to the about ±0.5° C. variation in temperature ofthe heated environment.
 10. The method of claim 9 wherein the allowedvariation in temperature of the heated environment is at least about ±1°C. and the detector is insensitive to the about ±1° C. variation intemperature of the heated environment.
 11. The method of claim 9 whereinthe allowed variation in temperature of the heated environment is atleast about ±2° C. and the detector is insensitive to the about ±2° C.variation in temperature of the heated environment.
 12. The method ofclaim 9 wherein the allowed variation in temperature of the heatedenvironment is at least about ±5° C. and the detector is insensitive tothe about ±5° C. variation in temperature of the heated environment. 13.The method of claim 9 wherein the heated environment is maintained to benot less than about 100° C.
 14. The method of claim 9 wherein the heatedenvironment is maintained to be not less than about 125° C.
 15. Themethod of claim 9 wherein the heated environment is maintained to be notless than about 150° C.
 16. A method for characterizing a polymersample, the method comprising preparing a chromatographic column forseparation by heating the column from about ambient temperature to about75° C. in less than about 1 hour, separating at least one samplecomponent of a polymer sample from other sample components thereof inthe heated chromatographic column, and detecting a property of at leastone of the separated sample components.
 17. The method of claim 16wherein the chromatographic column is heated from about ambienttemperature to about 75° C. in less than about 30 minutes.
 18. Themethod of claim 16 wherein the chromatographic column is heated fromabout ambient temperature to about 100° C. in less than about 1 hour.19. The method of claim 16 wherein the chromatographic column is heatedfrom about ambient temperature to about 100° C. in less than about 30minutes.
 20. The method of claim 16 wherein the chromatographic columnis heated from about ambient temperature to about 125° C. in less thanabout 1 hour.
 21. The method of claim 16 wherein the chromatographiccolumn is heated from about ambient temperature to about 125° C. in lessthan about 30 minutes.
 22. The method of claim 16 wherein thechromatographic column is heated from about ambient temperature to about150° C. in less than about 1 hour.
 23. The method of claim 16 whereinthe chromatographic column is heated from about ambient temperature toabout 150° C. in less than about 30 minutes.
 24. A method forcharacterizing a polymer sample, the method comprising loading a polymersample into a liquid chromatography system, maintaining the loadedpolymer sample at a temperature of not less than 75° C., eluting one ormore sample components of the polymer sample with a mobile-phase eluanthaving a temperature of not less than about 75° C., controlling thecomposition of the mobile-phase eluant to vary over time to separate atleast one sample component of the sample from other sample componentsthereof, and detecting a property of at least one of the separatedsample components.
 25. The method of claim 24 wherein the loaded polymersample is maintained at a temperature of not less than 100° C. and themobile-phase eluant has a temperature of not less than about 100° C. 26.The method of claim 24 wherein the loaded polymer sample is maintainedat a temperature of not less than 125° C. and the mobile-phase eluanthas a temperature of not less than about 125° C.
 27. The method of claim24 wherein the loaded polymer sample is maintained at a temperature ofnot less than 150° C. and the mobile-phase eluant has a temperature ofnot less than about 150° C.
 28. A method for characterizing a polymersample, the method comprising loading a polymer sample into a liquidchromatography system, eluting one or more sample components of thepolymer sample with a mobile-phase eluant, controlling the temperatureof the mobile-phase eluant to vary over time to separate at least onesample component of the sample from other sample components thereof, anddetecting a property of at least one of the separated sample components.29. The method of claim 28 wherein the loaded polymer sample comprisesat least one precipitated sample component.
 30. The method of claim 28wherein the polymer sample comprises one or more sample components thatare insoluble at a temperature of less than about 75° C.
 31. The methodof claim 28 wherein the polymer sample comprises one or more samplecomponents that are insoluble at a temperature of less than about 100°C.
 32. The method of claim 28 wherein the polymer sample comprises oneor more sample components that are insoluble at a temperature of lessthan about 125° C.
 33. The method of claim 28 wherein the polymer samplecomprises one or more sample components that are insoluble at atemperature of less than about 150° C.
 34. The method of claim 28wherein the chromatographic column comprises a stationary phase and thepolymer sample comprises one or more sample components that arenon-desorbing from the stationary phase at a temperature of less thanabout 75° C.
 35. The method of claim 28 wherein the chromatographiccolumn comprises a stationary phase and the polymer sample comprises oneor more sample components that are non-desorbing from the stationaryphase at a temperature of less than about 100° C.
 36. The method ofclaim 28 wherein the chromatographic column comprises a stationary phaseand the polymer sample comprises one or more sample components that arenon-desorbing from the stationary phase at a temperature of less thanabout 125° C.
 37. The method of claim 28 wherein the chromatographiccolumn comprises a stationary phase and the polymer sample comprises oneor more sample components that are non-desorbing from the stationaryphase at a temperature of less than about 150° C.
 38. The method ofclaim 28 further comprising controlling the temperature of thechromatographic column.
 39. A method for characterizing a polymersample, the method comprising loading a polymer sample into a liquidchromatography system having a chromatographic column, eluting thecolumn with a mobile phase, controlling the temperature of the columnwhile eluting the column with the mobile phase such that at least onesample component of the loaded sample is separated from other samplecomponents thereof, and detecting a property of at least one of theseparated sample components.
 40. The method of claim 39 wherein themobile phase is supplied to the column at about a constant temperature.41. The method of claim 39 further comprising controlling thetemperature of the column while loading the sample onto the column. 42.The method of claim 39 further comprising controlling the temperature ofthe column while loading the sample such that at least one samplecomponent precipitates or adsorbs onto the stationary phase.
 43. Anapparatus for automated sampling of polymer samples forcharacterization, the apparatus comprising a probe having a surfacedefining a sample-cavity and an inlet port for fluid communicationbetween the sample cavity and a polymer sample, the probe being adaptedfor fluid communication with an injection port or a loading port of acontinuous-flow polymer characterization system, a microprocessor forcontrolling three-dimensional motion of the probe between variousspatial addresses, a pump for withdrawing a polymer sample into theprobe, and a temperature-control element in thermal communication withthe probe for maintaining a polymer sample residing in the probe at apredetermined temperature or within a predetermined range oftemperatures.
 44. The apparatus of claim 43 wherein thetemperature-control element is a heating element for maintaining asample residing in the probe at a temperature of not less than about 75°C.
 45. The apparatus of claim 43 wherein the temperature-control elementis a heating element for maintaining a sample residing in the probe at atemperature of not less than about 100° C.
 46. The apparatus of claim 43wherein the temperature-control element is a heating element formaintaining a sample residing in the probe at a temperature of not lessthan about 125° C.
 47. The apparatus of claim 43 wherein thetemperature-control element is a heating element for maintaining asample residing in the probe at a temperature of not less than about150° C.
 48. The apparatus of claim 43 wherein the temperature-controlelement is a cooling element.
 49. A liquid chromatography system forcharacterizing a polymer sample, the system comprising an enclosuredefining a heated environment, the heated environment being maintainedat a temperature of not less than about 75° C. and having at least about±0.5° C. variation in temperature, a chromatographic column residing inthe heated environment, the chromatographic column comprising a surfacedefining a pressurizable separation cavity, an inlet port for receivinga mobile phase and for supplying a polymer sample to the separationcavity, an effluent port for discharging the mobile phase and thepolymer sample or separated components thereof from the separationcavity, and a stationary-phase within the separation cavity, aninjection port or a loading port adaptable for fluid communication withthe chromatographic column for injecting polymer samples into the mobilephase, a reservoir in fluid communication with the inlet port of thechromatographic column for providing a mobile phase thereto andadaptable for fluid communication with the injection port, and adetector in fluid communication with the effluent port of thechromatographic column for detecting a property of at least one of thesample components, the detector being insensitive to variations intemperature of about ±0.5° C.
 50. The system of claim 49 wherein theheated environment is maintained at a temperature of not less than about100° C.
 51. The system of claim 49 wherein the heated environment ismaintained at a temperature of not less than about 125° C.
 52. Thesystem of claim 49 wherein the heated environment is maintained at atemperature of not less than about 150° C.
 53. The system of claim 49wherein the heated environment is maintained at a temperature of notless than about 100° C. and has at least about ±1° C. variation intemperature, the detector being insensitive to the variations intemperature of about ±1° C.
 54. The system of claim 49 wherein theheated environment is maintained at a temperature of not less than about100° C. and has at least about ±2° C. variation in temperature, thedetector being insensitive to the variations in temperature of about ±2°C.
 55. The system of claim 49 wherein the heated environment ismaintained at a temperature of not less than about 100° C. and has atleast about ±5° C. variation in temperature, the detector beinginsensitive to the variations in temperature of about ±5° C.
 56. Thesystem of claim 49 wherein the detector is an evaporative lightscattering detector.
 57. A liquid chromatography system forcharacterizing a po lym er sample, the system comprising an enclosuredefining a heated environment, the heated environment being maintainedat a temperature of not less than about 75° C., a chromatographic columnresiding in the heated environment, the chromatographic columncomprising a surface defining a pressurizable separation cavity, aninlet port for receiving a mobile phase and for supplying a polymersample to the separation cavity, an effluent port for discharging themobile phase and the polymer sample or separated components thereof fromthe separation cavity, and a stationary-phase within the separationcavity, an injection port adaptable for fluid communication with thechromatographic column for injecting polymer samples into the mobilephase, a first reservoir for containing a first mobile phase fluid, asecond reservoir for containing a second mobile phase fluid, a mixingzone adaptable for fluid communication with the first reservoir and thesecond reservoir for mixing of the first and second mobile phases toform a mobile-phase eluant having compositions or temperatures that canvary over time, the mixing zone being further adaptable for fluidcommunication with the inlet port of the chromatographic column foreluting one or more sample components of the sample with themobile-phase eluant to separate at least one sample component of thesample from other sample components thereof, and a detector in fluidcommunication with the effluent port of the chromatographic column fordetecting a property of at least one of the sample components.
 58. Thesystem of claim 57 further comprising a third reservoir for containing athird mobile-phase fluid, the third reservoir being adaptable for fluidcommunication with the mixing zone for mixing of the third mobile-phasefluid with one or both of the first or second mobile-phase fluids. 59.The system of claim 57 wherein the mixing zone is directly upstream ofthe column inlet port.
 60. The system of claim 57 wherein the columncomprises two inlet ports and the mixing zone is within the column. 61.A liquid chromatography system for characterizing a polymer sample, thesystem comprising a chromatographic column comprising a surface defininga pressurizable separation cavity, an inlet port for receiving a mobilephase and for supplying a polymer sample to the separation cavity, aneffluent port for discharging the mobile phase and the polymer sample orseparated components thereof from the separation cavity, and astationary phase within the separation cavity, an injection port or aloading port adaptable for fluid communication with the chromatographiccolumn for injecting polymer samples into the mobile-phase, a reservoirfor containing a mobile phase fluid, the reservoir being adaptable forfluid communication with the inlet port of the chromatographic column, aheater for controlling the temperature of the mobile-phase fluid or forcontrolling the temperature of the column, such that one or more samplecomponents of the polymer sample can be eluted with a mobile-phase fluidhaving a temperature that varies over time to separate at least onesample component of the sample from other sample components thereof, anda detector in fluid communication with the effluent port of thechromatographic column for detecting a property of at least one of thesample components.
 62. The system of claim 61 further comprising anenclosure defining a heated environment in which the chromatographiccolumn resides, the heated environment being maintained at a temperatureof not less than about 75° C.,
 63. The system of claim 62 wherein theheated environment is maintained at a temperature of not less than about100° C.
 64. The system of claim 62 wherein the heated environment ismaintained at a temperature of not less than about 125° C.
 65. Thesystem of claim 62 wherein the heated environment is maintained at atemperature of not less than about 150° C.
 66. The system of claim 61wherein the heater is a heating element in thermal communication withthe reservoir.
 67. The system of claim 61 wherein the heater is aheating element in thermal communication with a mobile-phase fluidtransfer line.
 68. The system of claim 61 wherein the heater is anenclosure defining a heated environment in which a length of amobile-phase fluid transfer line resides.
 69. The system of claim 61wherein the heater is a heating element in thermal communication withthe chromatographic column.